Category: Oncology — Integrative Oncology, Herbal Safety and Cancer Myths
Does boiled papaya leaf or papaya leaf juice cure cancer? Myth vs fact: lab-dish studies vs human evidence, risks of concentrated leaf juice, drug interactions, and the danger of replacing treatment
AI Overview / Quick Answer (BLUF)
Papaya-leaf compounds slow cancer cells only in lab dishes, at concentrations unproven in human blood; no human trial shows cure or longer survival.
Concentrated juice can irritate the gut, cause allergy or boost anticoagulants. Proven danger: replacing treatment, 2.5× death risk
(Johnson 2018).
What this page covers, and what to read alongside it
- This page focuses on papaya leaf and cancer: where the belief comes from, what level of evidence really exists, the risks of concentrated fresh leaf juice, drug interactions, and how to use integrative care safely without giving up standard treatment
- Herbs vs radiation in nasopharyngeal cancer → Radiotherapy or herbs: nasopharyngeal cancer
- How to get enough energy and protein during treatment → Cancer nutrition: Thai desserts and extra energy
- Fever during chemotherapy → Fever after chemo (febrile neutropenia): a caregiver guide
A question from a cancer support group: “Has anyone boiled papaya leaves to treat cancer? Does it really cure, or is it a lie?”
Direct answer: no human study has shown that papaya leaf cures cancer or helps people live longer — but it is not entirely “a lie” either, because real laboratory research exists; it simply sits on the first rung of the evidence ladder.
Wanting to try every option for someone you love is understandable and not wrong. What matters is using that hope safely: do not stop or delay standard treatment, and tell the treating team before starting any herb.
Red flags — stop the herb and go to hospital now
Direct answer: if any of the signs below appear after drinking papaya leaf juice or any herbal remedy, stop immediately and go to hospital, bringing the bottle, recipe or leaves you used — these can signal liver injury, dehydration, severe allergy, bleeding, or infection during chemotherapy.
- Yellow eyes or skin, dark urine, right upper abdominal pain, whole-body itching, or severe loss of appetite — signs of liver injury
- Much less urine, or swollen legs or face — kidney tests needed
- Persistent vomiting or diarrhea with inability to drink, dry mouth, or dizziness on standing — signs of dehydration
- Palpitations, fainting, near-fainting, or an unusually slow pulse
- Hives, lip or face swelling, wheezing — severe allergy, especially in people allergic to natural rubber latex
- Easy bleeding, bruising, nosebleeds, black stools — especially on anticoagulants or with low platelets from chemotherapy
- Fever ≥38.0 °C during chemotherapy — possible febrile neutropenia; go to hospital right away. Read the fever-after-chemo guide
1. Where the “papaya leaf cures cancer” belief comes from
Direct answer: the belief comes from folk medicine, personal stories, and cell-culture research — the lowest rung of evidence. No human study has measured tumor shrinkage or survival,
and news that papaya leaf raises platelets in dengue is often retold until it becomes “it cures cancer.”
(Otsuki N, J Ethnopharmacol 2010)
What lab-dish studies actually found
- Otsuki and colleagues (University of Tokyo, 2010) said their work began with anecdotes of patients with advanced cancer who drank papaya leaf tea. An aqueous leaf extract slowed several cancer cell lines in dishes and increased some immune signals (IL-12, IFN-γ, TNF-α) from white blood cells in test tubes; the active part was a small-molecule fraction under 1,000 daltons
— not the enzyme papain that people often imagine “digests cancer cells.” - A 2018 study in prostate cancer cells isolated a combination of fractions from papaya leaf juice that slowed cancer cells at an IC50 below 20 µg/mL, with less effect on normal cells — but all of this was in dishes.
(Pandey S, Front Pharmacol 2018)
Why a dish result is not a body result
- In a dish, cells sit directly in the extract. In the body, compounds must survive digestion, absorption and the liver first — no study has shown whether blood or tumor levels after drinking papaya leaf juice reach the concentrations used in dishes.
- Some studies report more effect on cancer cells than normal cells, but only in dishes — not yet shown in animals or people with tumors.
- Thousands of substances, including disinfectants, kill cancer cells in a dish — killing cells in a dish does not make something a medicine.
What a search for human studies found (September 2026)
we found no human study measuring tumor shrinkage, disease control or survival with papaya leaf, and almost no animal studies measuring tumor shrinkage in tumor-bearing animals.
The studies in cancer patients that do exist looked only at low platelets from chemotherapy (see section 2).
How dengue news gets retold wrongly
Papaya leaf has human studies on raising platelets in dengue fever — this gets passed along as “papaya leaf restores blood and fights cancer,” even though a platelet rise has nothing to do with killing cancer cells.
A 2020 review summarized that papaya leaf contains alkaloids, glycosides, tannins, saponins and flavonoids, and that clinical trials are still needed.
(Singh SP, Daru 2020)
Evidence-ladder table: from cell culture to phase 3 human trials — where papaya leaf stands
| Evidence level | Question it answers | What papaya leaf has at this level | What it would take to be proven |
|---|---|---|---|
| 1. Cell culture (in vitro) | Does the substance affect cancer cells under controlled conditions? | Yes — slows several cancer cell lines in dishes (Otsuki 2010, Pandey 2018) | A clearly identified active compound and concentrations the body can actually reach |
| 2. Tumor-bearing animals | Do tumors shrink with oral dosing, and is the effective dose safe? | Almost none found on PubMed — animal work mainly covers platelets and safety, e.g. rats given extract for 180 days showed no toxicity | Tumor shrinkage or longer survival replicated across labs, with blood levels measured |
| 3. Human phase 1 | What dose is safe, and how is it absorbed and cleared? | None found in cancer patients for treating cancer (only safety data from platelet studies) | A standardized extract, blood-level measurements, and dose-related side effects |
| 4. Human phase 2 | Do tumors shrink in a small group of patients? | None found | Tumor response rates by standard criteria (e.g. RECIST) |
| 5. Human phase 3 randomized | Do patients live longer or have better disease control than with standard care? | None for cancer treatment — only a trial on chemotherapy-induced low platelets (Ostwal 2026), which carries a journal expression of concern | Significantly better survival or disease-free survival, replicated across centers |
Summarized from Otsuki 2010, Pandey 2018, Taychaworaditsakul 2024 and Ostwal 2026 — most anti-cancer candidates that pass level 1 never reach level 5.
2. What papaya leaf does have human evidence for: platelets, not cancer treatment
Direct answer: almost all human evidence for papaya leaf concerns raising platelets in dengue, which a meta-analysis rated as low-quality evidence. Studies on chemotherapy-induced low platelets are emerging but not standard care — and none measured cancer control.
(Rajapakse S, BMC Complement Altern Med 2019)
Dengue: randomized trials and meta-analysis
- Malaysia: 228 patients with dengue randomized to 3 days of papaya leaf juice vs standard care; platelets were higher in the juice group at 40–48 hours (open-label).
(Subenthiran S, 2013) - India: 300 patients across 5 centers, double-blind vs placebo, extract tablets three times daily for 5 days; platelets rose faster. The main side effects were nausea and vomiting, similar in both groups.
(Kasture PN, 2016) - Meta-analysis of 9 studies: hospital stay may be about 1.98 days shorter, but evidence was low quality, and there were no data on serious complications or deaths. The authors concluded the evidence is insufficient to define its role in dengue.
Low platelets from chemotherapy: new research, not yet standard
- A randomized, blinded phase 3 trial from India (2026): 219 patients (198 analyzed) with chemotherapy-induced low platelets received standardized extract tablets or placebo; more reached 75,000 per microliter by day 4, 59% vs 44%, with no grade 3–4 side effects.
(Ostwal V, JCO Glob Oncol 2026) - The journal issued an expression of concern about this trial in July 2026 — so the result awaits further review.
- A 2025 meta-analysis (410 patients) suggested a platelet benefit but with high risk of bias and heterogeneity; doses ranged from 580 to 3,300 mg per day.
(Mîrșu-Păun A, Nutr Health 2025)
3. Risks of concentrated fresh papaya leaf juice
Direct answer: most people who drank it in trials had no serious side effects, but homemade concentrated juice has an unknown dose and can cause nausea and vomiting, allergy, or problems in higher-risk groups such as people with latex allergy, pregnant women, and patients with low white cells.
Human toxicity data are limited — that does not mean it is safe, and it does not mean harm is certain.
Papaya leaf compounds table: reported activity, risk when fresh or concentrated, and cautions
| Compound group | Reported activity (mostly lab/animal) | Risk when fresh/concentrated | Caution |
|---|---|---|---|
| Flavonoids and phenolics (e.g. quercetin, kaempferol) | Antioxidant, anti-inflammatory, slows cancer cells in dishes | Poorly absorbed by mouth; blood levels far below dish levels; effects on drug-clearing liver enzymes are theoretical | Avoid concentrated use during chemotherapy or targeted therapy without telling the team |
| Carpaine (alkaloid) | Anti-dengue-virus activity in test tubes, anti-inflammatory in animals | In rats given 0.5–2.0 mg/kg, blood pressure fell with dose and cardiac output dropped — human data are limited | Take care with heart disease, low blood pressure, or blood-pressure and heart-rhythm medicines |
| Papaya latex: papain, chymopapain and chitinase | Protein-digesting enzymes (not shown to kill cancer cells in people) | Irritates mouth, throat and stomach; main papaya allergens; crude latex made rat uterus contract like a labor-inducing drug | Avoid with latex (rubber-glove) allergy, food-allergy history, or pregnancy |
| Others: saponins, tannins, glycosides | Antimicrobial, glucose-lowering in animals | Very bitter, irritates the gut; glucose-lowering may add to diabetes medicines | People with diabetes should check glucose more often and tell the team |
Summarized from Singh 2020, Hornick 1978, Rojas-Mandujano 2018 and Adebiyi 2002
Gut irritation
The most common side effects in trials were nausea and vomiting — for patients already nauseated from chemotherapy, a very bitter leaf juice may reduce how much they can eat, which works against nutrition goals.
Carpaine, the heart and blood pressure: animal data, limited human data
In rats given carpaine at 0.5–2.0 mg/kg, blood pressure fell with increasing dose, and at 2 mg/kg cardiac output dropped; the authors concluded it acts directly on heart muscle.
(Hornick CA, 1978)
— there are no data on whether drinking leaf juice delivers carpaine at these levels, so the fair conclusion is caution in people with heart disease, not certain harm.
Papaya latex allergy and latex-fruit syndrome
Papain and chymopapain are the main papaya allergens and resemble proteins in natural rubber latex, so people allergic to rubber gloves may also react to papaya (latex-fruit syndrome). In a group of 11 patients with latex allergy, all had a history of papaya-induced anaphylaxis.
(Rojas-Mandujano V, 2018)
A 2024 review found latex-fruit syndrome in 4–88% of latex-allergic patients, with papaya among the most common fruits involved.
(Gromek W, J Clin Med 2024)
Pregnancy: avoid unripe papaya latex and concentrated leaf
In isolated rat uterus experiments, crude papaya latex at 0.2 mg/mL caused contractions comparable to oxytocin, while ripe papaya had no such effect.
(Adebiyi A, Br J Nutr 2002)
Leaves and unripe fruit are rich in latex, so anyone who is or may be pregnant should avoid them — eating ripe papaya as ordinary fruit is not the issue.
Herb-induced liver injury: the risk of herbs as a group
In the US Drug-Induced Liver Injury Network, 15.5% of liver-injury cases (130 of 839) were caused by herbal and dietary supplements, rising from 7% to 20% between 2004 and 2013,
and non-bodybuilding supplement injury ended in death or liver transplant in 13% vs 3% for conventional-drug injury.
(Navarro VJ, Hepatology 2014)
— these figures are for all herbs combined. We did not find a papaya-leaf-specific liver injury case series on PubMed, and a rat study from Chiang Mai University’s Faculty of Medicine found no organ toxicity from a 10% ethanolic leaf extract at up to 5,000 mg/kg daily for 180 days.
(Taychaworaditsakul W, Toxics 2024)
But rat results with a standardized extract do not guarantee the safety of homemade juice in patients whose livers are already working hard during chemotherapy.
Homemade juice: uncertain dose and contamination risk
- Strength varies with leaf age, variety, amount of water and pounding method — no one knows how much of any compound each glass contains
- Unheated fresh juice can carry germs from soil, hands or utensils — more dangerous for patients with low white cells during chemotherapy
- Leaves from unknown sources may carry pesticide residues
How urgently do current symptoms during cancer treatment need the team?
Analyze symptom severity and get personalized guidance from our Advisory team.
For yellow eyes, fever ≥38.0 °C during chemotherapy, facial swelling, wheezing, or unusual bleeding, go to hospital first — no need to take the score first.
Take the Cancer-Care Warning-Sign Score (free)
4. Papaya leaf and cancer-treatment medicines: interactions to know
Direct answer: the clearest human-reported interaction is papaya with the anticoagulant warfarin, causing over-anticoagulation. Effects on chemotherapy through liver enzymes remain theoretical — but because nobody knows for sure, oncology teams usually ask patients to pause herbs around chemotherapy.
(Izzo AA, Int J Cardiol 2005)
Anticoagulants and antiplatelet medicines
- A review of case reports found warfarin interacting with several herbs, including papaya, resulting in excessive anticoagulation; papain is on the list of products with documented reports of warfarin interaction.
(Heck AM, 2000) - People taking antiplatelet medicines such as aspirin or clopidogrel, or newer oral anticoagulants, should tell the team before using any herb.
- Patients with low platelets from chemotherapy already have a bleeding risk — do not use herbs to “push platelets up” instead of the team’s care.
Liver enzymes and drug transporters: a theoretical risk
Many chemotherapy, targeted and hormonal drugs are cleared through CYP450 liver enzymes and drug transporters, and some plant compounds can raise or lower drug levels. For papaya leaf, no human drug-level studies exist, so it cannot be called safe or dangerous — that uncertainty is exactly why the team asks to know everything the patient takes.
Diabetes medicines
Papaya leaf extract lowered glucose in animal studies. Patients on insulin or oral diabetes medicines (such as metformin or sulfonylureas) who are also eating little during chemotherapy may be at risk of low blood sugar — check glucose more often if using it, and tell the team.
Why oncology teams often ask to pause herbs around chemotherapy
- If liver or kidney tests rise during chemotherapy, the team needs to know whether the drug or the herb is responsible, to avoid cutting or stopping chemotherapy unnecessarily.
- Herbs with unknown doses make interactions impossible to predict.
- The pause is often short, around treatment days, not a lifelong ban — ask the team which windows are safe.
If the patient insists on using it: how to reduce risk
- Tell the doctor and pharmacist, and bring the bottle, recipe or a photo of the leaves.
- Ask for liver tests (LFT) and kidney tests (creatinine) before starting and at intervals the team sets; people on warfarin need more frequent INR checks.
- Use one herb at a time, not mixtures, so the cause is clear if symptoms appear.
- Stop immediately at any red-flag sign listed above.
5. The biggest danger: replacing or delaying standard treatment
Direct answer: the best-documented risk is not papaya leaf toxicity but using herbs instead of standard treatment — patients with curable cancer who chose alternative medicine alone had about a 2.5 times higher risk of death.
(Johnson SB, J Natl Cancer Inst 2018)
Alternative medicine alone (JNCI 2018)
281 patients with non-metastatic breast, prostate, lung or colorectal cancer who chose alternative medicine alone, compared with patients receiving standard treatment: risk of death HR 2.50 (95% CI 1.88–3.27)
— breast cancer 5.68 times, colorectal cancer 4.57 times, lung cancer 2.17 times.
Complementary medicine alongside, but refusing parts of treatment (JAMA Oncology 2018)
In patients with curable cancers, 258 complementary-medicine users vs 1,032 controls: refused surgery 7.0% vs 0.1%, chemotherapy 34.1% vs 3.2%, radiation 53.0% vs 2.3%;
5-year survival 82.2% vs 86.6%, and risk of death HR 2.08 — but once treatment refusal or delay was added to the model, the difference was not significant (HR 1.39).
(Johnson SB, JAMA Oncol 2018)
Comparison table: standard treatment alone, standard plus evidence-based integrative care, standard plus team-approved herbs, and herbs instead of standard treatment
| Approach | Evidence level | Survival impact | Main risks | When appropriate |
|---|---|---|---|---|
| Standard treatment alone (surgery, chemotherapy, radiation, targeted therapy, immunotherapy, hormonal therapy) | High — phase 3 randomized trials and clinical guidelines | Proven to increase cure or extend life, depending on cancer type and stage | Treatment side effects, which the team has ways to prevent and manage | The core for every patient who can be treated, following the team’s plan |
| Standard + evidence-based integrative care (exercise, nutrition support, acupuncture/acupressure, meditation, yoga, music therapy) | Moderate to high for symptom relief, per SIO–ASCO guidelines | Not designed to treat cancer, but improves quality of life, stress, nausea and pain, helping patients tolerate treatment | Low — caution with acupuncture when platelets or white cells are low; tailor exercise to fitness | Almost everyone, discussing timing and intensity with the team |
| Standard + herbal products the oncology team knows about and approves (e.g. papaya leaf) | Low for treating cancer (papaya leaf has only lab-dish data) | No evidence of benefit — but no loss if standard treatment continues | Drug interactions, abnormal liver or kidney tests, allergy, gut irritation, harder-to-read blood tests | When the patient truly wants it, the team knows, blood tests are monitored, and pauses are respected |
| Herbal/alternative medicine instead of standard treatment | Evidence of harm (large observational studies) | About 2.5 times higher risk of death in curable cancers | Disease progression and lost chance of cure, plus the herb’s own risks | Not recommended — if the patient does not want standard treatment, discuss palliative care with the team instead |
Summarized from Johnson 2018 JNCI, Johnson 2018 JAMA Oncol, Lyman 2018 and Mao 2022 — not individual advice.
6. A safer path: use hope together with the treating team
Direct answer: tell the oncology team and hospital pharmacist about everything the patient takes, bring the bottle or recipe, choose evidence-based integrative care for symptoms, and never stop or delay standard treatment — the SIO–ASCO guideline states there is no strong evidence that ingested dietary supplements help manage treatment side effects.
(Lyman GH, J Clin Oncol 2018)
How to tell the team in a useful way
- List every medicine, herb, vitamin and supplement, with dose and frequency.
- Bring bottles, labels, or the boiling/pounding recipe for the doctor and pharmacist to see.
- Ask directly: “When should we pause?” “What extra blood tests are needed?” “Is there a better-evidenced option for this symptom?”
- Disclosure is not about being scolded — the team needs the information to keep the patient safe.
Evidence-based integrative care (SIO–ASCO guidelines)
- Music therapy, meditation, stress management and yoga — for stress and anxiety
- Acupuncture and acupressure — for chemotherapy nausea and vomiting
- Acupuncture, acupressure or massage — for certain types of pain, per the 2022 pain guideline
(Mao JJ, J Clin Oncol 2022) - Exercise as tolerated, such as walking 10–20 minutes a day, and nutrition support for enough energy and protein — read the cancer nutrition guide and nutrition when exhausted and eating little
Thailand context: who to ask
- Hospital pharmacists — check interactions between herbs and prescribed medicines
- Many public hospitals have Thai traditional medicine or integrative medicine clinics that work with conventional doctors — services and coverage differ by hospital, so confirm with your hospital
- A Thai FDA registration number means a product is legally made — it does not mean it treats cancer. Be wary of ads claiming “complete cure” or “no chemo needed”
- Emergency in Thailand: call 1669
How to talk with a loved one without fighting
- Start from the shared goal: “We both want Mom to get better” rather than “Why do you believe that nonsense?”
- Offer a middle path: “You can try it, but tell the doctor first and don’t stop chemo.”
- Redirect toward what truly helps today, such as high-protein food, gentle walks and keeping appointments — read Chemo lesson 1: treatment-day checklist
Scientific mechanism (synthesized by the author)
Synthesized by
Asst. Prof. Dr. Norawit Raatpiboon:
in a culture dish, cancer cells bathe directly in papaya leaf extract for days, so phenolics and flavonoids can trigger programmed cell death (apoptosis via caspase-3/7) and halt the cell cycle.
When the juice is swallowed, however, most of these compounds are poorly absorbed, are converted by gut bacteria and the liver into conjugated forms (glucuronides and sulfates) that behave differently from the parent compound, and are cleared quickly.
Blood levels of such compounds are generally many times lower than the microgram-per-milliliter concentrations used in dishes — and real tumors add abnormal blood vessels, high interstitial pressure and supporting stromal cells that block penetration.
The platelet effect in dengue is a separate mechanism: data link it to expression of the ALOX12 and PTAFR genes and to reduced platelet destruction, which does not kill cancer cells.
On the risk side, papaya latex contains protein-digesting enzymes that irritate mucosa and provoke allergy, while carpaine’s large macrocyclic ring may chelate cations and reduced heart-muscle contraction in animals.
The gap between “kills cells in a dish” and “treats people” is therefore very wide, and it can only be closed by human trials, not by stories.
Frequently asked questions (FAQ)
Can boiled papaya leaf or papaya leaf juice cure cancer?
There is no evidence that it cures cancer. The studies showing anti-cancer activity were done on cells in lab dishes, at concentrations that have not been shown to be reached in human blood. A search of PubMed and ClinicalTrials.gov up to September 2026 found no human study measuring tumor shrinkage or survival with papaya leaf. It should not replace standard treatment, and the treating team should always be told if a family wants to use it alongside.
Why do people believe papaya leaf kills cancer cells?
The belief comes from three sources: long folk use, stories from individual patients, and laboratory research such as a 2010 study by Otsuki and colleagues in which an aqueous papaya leaf extract slowed the growth of several cancer cell lines in dishes. News that papaya leaf raises platelets in dengue is also often misread as a cancer treatment. Results in a lab dish do not mean the same effect happens in the human body.
Does papaya leaf really raise platelets, and can it be used for low platelets from chemotherapy?
In dengue, several randomized trials found platelets rose faster, but a 2019 meta-analysis rated the evidence as low quality. For chemotherapy-induced low platelets, a 2026 phase 3 trial from India used standardized extract tablets under oncology supervision and found more patients reached the target platelet level by day 4 than with placebo, 59% vs 44%, but the journal issued an expression of concern about the trial in July 2026. This is a platelet result, not cancer control, and it did not use homemade fresh juice, so it should not be self-prescribed.
Is drinking concentrated fresh papaya leaf juice dangerous?
It may not be safe for everyone. Concentrated fresh juice is very bitter and can cause nausea, vomiting or stomach pain. Papaya latex contains the enzymes papain and chymopapain, which can trigger allergy, especially in people allergic to natural rubber latex. Carpaine, an alkaloid in the leaf, lowered blood pressure and cardiac output in rats, but human toxicity data are limited. Homemade juice also has an unknown dose and may be contaminated, so patients with low white cells during chemotherapy need extra caution.
Can I drink papaya leaf juice during chemotherapy?
Always tell the oncologist and the hospital pharmacist first. Most oncology teams ask patients to pause all herbs around chemotherapy, because herbs can affect the liver or kidneys, make blood tests harder to interpret, and interact with other medicines such as the anticoagulant warfarin, where papaya has been reported to over-thin the blood. If the patient insists on using it, ask the team to check liver and kidney tests regularly.
Can herbs alone replace chemotherapy or radiation?
No. This is the best-documented danger. A 2018 study using a large US cancer database found that patients with curable, non-metastatic cancer who chose alternative medicine alone had about a 2.5 times higher risk of death than those who received standard treatment, and about 5.7 times higher in breast cancer.
Is it harmful to use herbs alongside standard treatment?
The main problem is usually not the herb itself. A 2018 JAMA Oncology study found that complementary medicine users refused standard treatment more often, for example chemotherapy 34.1% vs 3.2% and radiation 53.0% vs 2.3%, and had about twice the risk of death. Once treatment refusal or delay was included in the analysis, the difference was no longer statistically significant, meaning the harm came mainly from skipping or delaying treatment. Use alongside treatment should be open with the team and never reduce standard care.
Which integrative therapies have evidence for people with cancer?
SIO and ASCO guidelines support integrative therapies to relieve symptoms, not to treat cancer. Examples include music therapy, meditation, stress management and yoga for stress and anxiety, acupuncture and acupressure for chemotherapy nausea and vomiting, and acupuncture, acupressure or massage for certain types of pain. The same guideline states there is no strong evidence that ingested dietary supplements help manage breast cancer treatment side effects.
Which symptoms after drinking papaya leaf juice mean I should stop and go to hospital?
Stop and go to hospital for yellow eyes or skin, dark urine, right upper abdominal pain, much less urine or swelling, vomiting or diarrhea with dehydration, palpitations, fainting or a very slow pulse, hives, lip or face swelling, wheezing, or unusual bleeding or bruising. A fever of 38.0 °C or higher during chemotherapy needs hospital care right away because it may be febrile neutropenia.
E-E-A-T and academic citations
Written by Asst. Prof. Dr. Norawit Raatpiboon (ผศ.ดร.นรวิชญ์ ราษฎร์พิบูลย์) — synthesized from PubMed research, SIO–ASCO guidelines, and a ClinicalTrials.gov registry search (September 2026)
- Otsuki N, et al. Aqueous extract of Carica papaya leaves exhibits anti-tumor activity and immunomodulatory effects. J Ethnopharmacol 2010 (PMID 19961915)
- Pandey S, et al. Bio-Guided Fractionation of Papaya Leaf Juice for Delineating the Components Responsible for the Selective Anti-proliferative Effects on Prostate Cancer Cells. Front Pharmacol 2018 (PMID 30505274)
- Singh SP, et al. Therapeutic application of Carica papaya leaf extract in the management of human diseases. Daru 2020 (PMID 32367410)
- Subenthiran S, et al. Carica papaya Leaves Juice Significantly Accelerates the Rate of Increase in Platelet Count among Patients with Dengue Fever and Dengue Haemorrhagic Fever. Evid Based Complement Alternat Med 2013 (PMID 23662145)
- Kasture PN, et al. A Multi-centric, Double-blind, Placebo-controlled, Randomized, Prospective Study of Carica papaya Leaf Extract for Thrombocytopenia associated with Dengue Fever. J Assoc Physicians India 2016 (PMID 27739262)
- Rajapakse S, et al. Carica papaya extract in dengue: a systematic review and meta-analysis. BMC Complement Altern Med 2019 (PMID 31601215)
- Ostwal V, et al. Carica Papaya Leaf Extract to Improve Chemotherapy-Induced Thrombocytopenia: A Phase III Triple-Blinded, Randomized, Placebo-Controlled, Multicentric Trial. JCO Glob Oncol 2026 — expression of concern July 2026 (PMID 41812092)
- Mîrșu-Păun A. Could Carica papaya leaf extract impact chemotherapy-induced thrombocytopenia? A systematic review and meta-analysis. Nutr Health 2025 (PMID 40836827)
- Hornick CA, et al. Effect of carpaine, a papaya alkaloid, on the circulatory function in the rat. Res Commun Chem Pathol Pharmacol 1978 (PMID 734216)
- Taychaworaditsakul W, et al. Safety of Oral Carica papaya L. Leaf 10% Ethanolic Extract for Acute and Chronic Toxicity Tests in Sprague Dawley Rats. Toxics 2024 (PMID 38535931)
- Rojas-Mandujano V, et al. Latex-papaya syndrome: an infrequent association. Rev Alerg Mex 2018 (PMID 29723936)
- Gromek W, et al. Revisiting Latex-Fruit Syndrome after 30 Years of Research. J Clin Med 2024 (PMID 39064262)
- Adebiyi A, et al. Papaya (Carica papaya) consumption is unsafe in pregnancy: fact or fable? Br J Nutr 2002 (PMID 12144723)
- Navarro VJ, et al. Liver injury from herbals and dietary supplements in the U.S. Drug-Induced Liver Injury Network. Hepatology 2014 (PMID 25043597)
- Izzo AA, et al. Cardiovascular pharmacotherapy and herbal medicines: the risk of drug interaction. Int J Cardiol 2005 (PMID 15676159)
- Heck AM, et al. Potential interactions between alternative therapies and warfarin. Am J Health Syst Pharm 2000 (PMID 10902065)
- Johnson SB, et al. Use of Alternative Medicine for Cancer and Its Impact on Survival. J Natl Cancer Inst 2018 (PMID 28922780)
- Johnson SB, et al. Complementary Medicine, Refusal of Conventional Cancer Therapy, and Survival Among Patients With Curable Cancers. JAMA Oncol 2018 (PMID 30027204)
- Lyman GH, et al. Integrative Therapies During and After Breast Cancer Treatment: ASCO Endorsement of the SIO Clinical Practice Guideline. J Clin Oncol 2018 (PMID 29889605)
- Mao JJ, et al. Integrative Medicine for Pain Management in Oncology: Society for Integrative Oncology-ASCO Guideline. J Clin Oncol 2022 (PMID 36122322)
- ClinicalTrials.gov — search results for “papaya leaf” (September 2026): dengue and chemotherapy-induced low-platelet studies found; no study measuring cancer treatment outcomes
Medical Disclaimer
This page provides general education about the evidence on papaya leaf in cancer, herbal safety, and integrative medicine —
it is not a diagnosis, prognosis, or individual treatment plan, and it does not recommend or endorse any product. Research figures describe specific patient groups and do not predict any individual’s outcome.
Medicines are named by generic name or drug class, not brand names. Do not stop, reduce, or delay cancer treatment on your own, and tell the treating doctor and pharmacist before using any herb or supplement.
Integrative-medicine services and coverage differ by provider — confirm with your hospital. For yellow eyes, fever ≥38.0 °C during chemotherapy, trouble breathing, facial swelling, bleeding, or any emergency, go to hospital or call emergency services (1669 in Thailand) immediately.