"Natural Cancer Cures" and Alternative Cancer Clinic Claims Checked
What cancer agencies and studies say about natural cancer cure claims and alternative cancer clinics, why delaying proven treatment is dangerous, and how to spot red flags.
Content last updated . This page has not been medically reviewed.
Urgent first
If you have a cancer diagnosis, talk with your oncology team before starting, stopping or replacing anything. For an emergency such as trouble breathing, severe bleeding, chest pain or a new seizure, call 911. If a diagnosis leaves you feeling hopeless or thinking about harming yourself, call or text 988 in the US. This page is information only and never a substitute for medical care. Do not stop or change prescribed cancer medicines, or skip surgery, radiation, screening or follow-up, because of anything you read here.The bottom line from cancer agencies
NCCIH says no complementary health approach has been shown to prevent or cure cancer. [1] It advises people not to use unproven products or practices to replace or delay medical treatment for cancer. [1] FDA says that legitimate cancer drugs and devices must gain FDA approval or clearance before they are sold. [2]Some complementary approaches do have a role in care. NCCIH says approaches such as acupuncture, mindfulness-based stress reduction and yoga may help manage cancer symptoms and side effects of treatment. [1] That is supportive care alongside treatment, not a cure. See integrative oncology supportive care guidelines.
Words matter: complementary vs alternative
The National Cancer Institute says complementary medicine is used along with standard medical treatment but is not itself standard treatment, while alternative medicine is used instead of standard treatment. [3] An example it gives is using a special diet to treat cancer instead of cancer drugs prescribed by an oncologist. [3] Our page on naturopathic and integrative care in cancer covers that distinction by practitioner type.What studies found about outcomes
| Study | What it found | Limits |
|---|---|---|
| Johnson et al., 2018, J Natl Cancer Inst | Among 281 people with non-metastatic breast, prostate, lung or colorectal cancer who chose alternative medicine as their only anticancer treatment, matched comparison showed greater risk of death than conventional treatment (hazard ratio 2.50) [4] | Observational; people choosing alternative medicine differed, for example by higher socioeconomic status [4] |
| Johnson et al., 2018, JAMA Oncology | In people who had conventional treatment plus unproven treatment from non-medical personnel, refusal of surgery, chemotherapy, radiotherapy and hormone therapy was higher [5]. The association with death was not significant once treatment delay or refusal was included [5] | Observational; the authors suggest risk was mediated by refusing conventional treatment [5] |
Read together, the studies point to refusing or delaying proven treatment as the main danger. For a plain-language summary, see what studies found about choosing alternative medicine instead of cancer treatment.
Specific claims checked
- Laetrile (amygdalin, also called "vitamin B-17"). The National Cancer Institute says laetrile has shown little anticancer effect in clinical studies and that FDA has not approved it for cancer or any other medical condition. [6] NCCIH says a 2019 review found no clinical evidence it is effective, and that laetrile can have toxic effects. [1] The NCI summary says laetrile treatments are given in Mexico and some US clinics, and that how it is made is not regulated by FDA, so batches may vary in purity and contents. [6]
- High-dose IV vitamin C. Results are mixed and mostly from animal and laboratory research; FDA has not approved it as a cancer treatment. [1][7] See IV vitamin drips and vitamin C claims.
- Herbs and supplements during treatment. NCCIH notes some herbs may make chemotherapy drugs less effective. [1] Tell your oncology team about everything you take; see integrative care during cancer treatment.
- Chelation or "detox" as a cancer treatment. FDA says there is no proof that chelation-based detoxification prevents or treats any condition or disease. [8] See chelation therapy.
Alternative cancer clinics
Proper evidence not found for outcomes at alternative cancer clinics as a group. We searched PubMed on 2026-10-22 for studies of outcomes in patients treated at alternative cancer clinics and the first results were unrelated to alternative clinics; web searches returned mainly blogs and news, which we did not use as evidence. The agency pages above cover specific products, not clinics as a category. Clinics differ, so judge any one by what it offers and promises, not by its label.Red flags
FDA lists phrases that signal a fraudulent cancer product, including "treats all forms of cancer," "miraculously kills cancer cells and tumors" and "shrinks malignant tumors." [2] FDA warns that such "natural" products can cause harm by delaying or interfering with proven treatment. [2] Other signs to question, based on our general guidance rather than a source here: a promise of cure, pressure to stop or delay your oncology care, secret remedies, and large payments demanded up front. See claim check: natural treatments cure cancer and evaluating safety claims.Frequently asked questions
Can a natural treatment cure cancer?
NCCIH says no complementary health approach has been shown to prevent or cure cancer. [1] Some approaches may help with symptoms alongside treatment. [1]
Is it safe to use alternative medicine instead of chemotherapy or surgery?
Studies in curable cancers linked alternative medicine alone with a higher risk of death, and NCCIH warns against replacing or delaying treatment. [4][1]
Does laetrile or "vitamin B-17" work?
NCI says it has shown little anticancer effect in clinical studies and is not FDA-approved for cancer. [6] NCCIH says it can have toxic effects. [1]
Is high-dose IV vitamin C a cancer treatment?
FDA has not approved it for that use, and evidence is mixed. [7][1]
What are the warning signs of a fake cancer cure?
FDA names claims such as treating all forms of cancer or miraculously killing cancer cells. [2]
More details: evidence, limits and cautions
The details behind this page: cautions, limits of the evidence and where sources disagree. Open any note to read it.
Who should check with a clinician first
Everyone with cancer, anyone in treatment, and anyone with cancer symptoms. FDA urges people to discuss cancer treatment options with a licensed health care provider. [2] To weigh options, ask for a second opinion from another oncology team, ask what the evidence is for any proposed treatment, and use coordinating complementary and medical care and how to evaluate a therapy claim.
References
- NCCIH, Cancer and Complementary Health Approaches: What You Need To Know. Read 2026-10-22.
- FDA, Products Claiming to "Cure" Cancer Are a Cruel Deception (content current as of 09/04/2020). Read 2026-10-22.
- National Cancer Institute, Complementary and Alternative Medicine (CAM). Read 2026-10-22.
- Johnson SB et al., Use of Alternative Medicine for Cancer and Its Impact on Survival, Journal of the National Cancer Institute 2018 (PubMed abstract). Read 2026-10-22.
- Johnson SB et al., Complementary Medicine, Refusal of Conventional Cancer Therapy, and Survival Among Patients With Curable Cancers, JAMA Oncology 2018 (PubMed abstract). Read 2026-10-22.
- National Cancer Institute, Laetrile/Amygdalin (PDQ), patient version (no longer updated). Read 2026-10-22.
- National Cancer Institute, Intravenous Vitamin C (PDQ), patient version. Read 2026-10-22.
- FDA, Questions and Answers on Unapproved Chelation Products (content current as of 02/02/2016). Read 2026-10-22.
Education, not medical advice. This page is for general information. It does not diagnose or treat any condition and is not a substitute for care from a qualified health professional. Natural does not automatically mean safe. Ask a clinician or pharmacist before changing your care, especially if you take medication, are pregnant or breastfeeding, or have a health condition.