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There’s a great deal of interest in complementary and integrative methods, and information can be found in a wide variety of sources. This can make it hard to know what's true and who to trust.
Unlike the case with drug treatments, treatments that do not make claims to treat specific diseases or side effects can be sold without having to be tested in scientific studies in the United States. This can lead to a lack of data about whether the treatment is safe and effective.
This is true for many dietary supplements. There are requirements about how dietary supplements must be made and labeled, but no requirements that they be tested to find out if they actually help, or if they are safe to use.
There have been some studies of complementary methods such as massage therapy and acupuncture. Most often they are shown to be safe, and some studies have found they may be helpful when used along with standard treatments.
Some people choose complementary therapies because they think they don’t have any harmful side effects. This may not be true. Some complementary therapies have been found to cause serious problems. Even so, most of these problems are not reported to the US Food and Drug Administration (FDA), so they are not studied.
For example, we know that certain vitamins and minerals can increase the risk of some cancers or other illnesses, especially if too much is taken. Also, it has been shown that some complementary methods can interfere with standard treatments.
However, many complementary mind-body methods are very safe. It’s rare for people to have problems with activities like meditation or music therapy.
Some people might think that treatments derived from natural products or from folk remedies that have been used for thousands of years must work and be safe. However, just because a treatment method is 'natural' or has been used a long time does not mean that it works and is safe.
When scientific studies have not been done, it can be hard to tell if a person's illness is getting better because of the treatment. Herbal treatments that are given for illnesses that go away on their own may be given credit for curing the person. Or the treatment might make the person feel better for a short time but have no lasting effect.
Controlled human studies (clinical trials) are the best way to find out if a treatment works. These studies typically include large groups of people, compare new treatments to treatments known to work, control who gets which treatment, and carefully measure the benefits and harms of each treatment. This can take a good bit of time and money. But clinical trials are vital to show that a treatment is safe and effective.
When looking for studies on a particular treatment, it is important to know whether a source can be trusted. It is best to look for studies published in reliable, mainstream medical journals.
If it’s hard to find information from a reliable expert source about a complementary method, it could mean that the method has not yet been studied enough to show if it works in people. The bottom line is that if you can’t find reliable information from researchers who don’t have a stake in the product, it’s likely that there isn't much proof that the method works in people.
Along with the American Cancer Society, the following is a partial list of websites and phone numbers of reputable groups that provide reliable information on complementary and alternative therapies*:
National Center for Complementary and Integrative Health (NCCIH)
Toll-free number: 1-888-644-6226 TTY: 1-866-464-3615
Has information on complementary and alternative therapy-related topics and clinical trials
Memorial Sloan Kettering Cancer Center About Herbs and Botanicals
Website: www.mskcc.org/cancer-care/integrative-medicine/about-herbs-botanicals-other- products
For evidence-based information about herbs, botanicals, supplements, and more
United States Department of Agriculture (USDA), Food and Nutrition Information Center
Find out about dietary supplements, vitamins, and minerals. Choose “Dietary Supplements” from the left menu bar.
National Cancer Institute’s Office of Cancer Complementary and Alternative Medicine
Offers in-depth information about complementary and alternative therapies with a focus on cancer. Includes sections on talking to your healthcare provider about CAM, information about specific therapies and frequently asked questions.
The American Cancer Society medical and editorial content team
Our team is made up of doctors and oncology certified nurses with deep knowledge of cancer care as well as journalists, editors, and translators with extensive experience in medical writing.
Deng G, Cassileth B. Integrative oncology: An overview. Am Soc Clin Oncol Educ Book. 2014:233-42. doi: 10.14694/EdBook_AM.2014.34.233. PMID: 24857081.
Greenlee H, DuPont-Reyes MJ, Balneaves LG, et al. Clinical practice guidelines on the evidence-based use of integrative therapies during and after breast cancer treatment. CA Cancer J Clin. 2017 May 6; 67(3):194-232.
Knecht K, Kinder D, Stockert A. Biologically-based complementary and alternative medicine (CAM) use in cancer patients: The good, the bad, the misunderstood. Front Nutr. 2020 Jan 24;6:196.
National Cancer Institute. Complementary and Alternative Medicine. Last updated November 24, 2020. Accessed at https://www.cancer.gov/about-cancer/treatment/cam on April 6, 2021.
National Cancer Institute’s Office of Cancer Complementary and Alternative Medicine. Health Information for Patients. Accessed from https://cam.cancer.gov/health_information/for_patients.htm on August 18, 2021.
National Center for Complementary and Integrative Health. Are You Considering a Complementary Health Approach? Last updated September 2016. Accessed at https://www.nccih.nih.gov/health/are-you-considering-a-complementary-health-approach on April 9, 2021.
Last Revised: August 25, 2021
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