• PC-SPES is a mixture of 8 herbs that was sold as a dietary supplement to keep the prostate healthy (see Question 1 ¹).



• Some batches of PC-SPES were found to contain prescription medicines. It was taken off the market and is no longer being made (see Question 1 ¹).



• Herbs in PC-SPES have been used in traditional Chinese medicine for many health problems, including prostate problems, for hundreds of years (see Question 2 ²).



• The herbs used in PC-SPES have been reported to help keep cancer cells from growing or help prevent cell damage that can lead to cancer (see Question 3 ³).



• Laboratory and animal studies suggested that PC-SPES might slow the growth of prostate cancer cells, but it is not known if these results were caused by the herbs in PC-SPES, prescription medicines that were found in the mixture, or both (see Question 5 ⁴).



• Clinical trials suggested that PC-SPES lowers PSA (prostate specific antigen) and testosterone levels in humans and has some anticancer effects. It is not known if these results were caused by the herbs in PC-SPES, prescription medicines that were found in the mixture, or both (see Question 6 ⁵).



• The National Center for Complementary and Alternative Medicine plans to do clinical trials of PC-SPES once a standard product is available (see Question 6 ⁵).



• The U.S. Food and Drug Administration has not approved PC-SPES for use in cancer treatment (see Question 8 ⁶).

Glossary Terms

A laboratory experiment using animals to study the development and progression of diseases. Animal studies also test how safe and effective new treatments are before they are tested in people.

A term for diseases in which abnormal cells divide without control. Cancer cells can invade nearby tissues and can spread to other parts of the body through the blood and lymph systems. There are several main types of cancer. Carcinoma is cancer that begins in the skin or in tissues that line or cover internal organs. Sarcoma is cancer that begins in bone, cartilage, fat, muscle, blood vessels, or other connective or supportive tissue. Leukemia is cancer that starts in blood-forming tissue such as the bone marrow, and causes large numbers of abnormal blood cells to be produced and enter the blood. Lymphoma and multiple myeloma are cancers that begin in the cells of the immune system. Central nervous system cancers are cancers that begin in the tissues of the brain and spinal cord.

The individual unit that makes up the tissues of the body. All living things are made up of one or more cells.

A type of research study that tests how well new medical approaches work in people. These studies test new methods of screening, prevention, diagnosis, or treatment of a disease. Also called clinical study.

A product that is added to the diet. A dietary supplement is taken by mouth, and usually contains one or more dietary ingredient (such as vitamin, mineral, herb, amino acid, and enzyme). Also called nutritional supplement.

An agency in the U.S. federal government whose mission is to protect public health by making sure that food, cosmetics, and nutritional supplements are safe to use and truthfully labeled. The Food and Drug Administration also makes sure that drugs, medical devices, and equipment are safe and effective, and that blood for transfusions and transplant tissue are safe. Also called FDA.

Having to do with plants.

A federal agency that uses science to explore complementary and alternative medicine (CAM) practices, trains CAM researchers, and provides authoritative information about CAM to professionals and the public. NCCAM awards grants for research projects, training, and career development in CAM; sponsors conferences, educational programs, and exhibits; studies ways to use proven CAM practices along with conventional medical practice; and supports adding CAM to medical, dental, and nursing school programs. NCCAM is part of the National Institutes of Health. Also called NCCAM.

A mixture of eight herbs that has been sold as a dietary supplement and promoted as a way to keep the prostate healthy and to treat prostate cancer. PC-SPES has been studied in the treatment of prostate cancer, but has been taken off the market in the U.S. because of safety concerns.

A doctor's order for medicine or another intervention.

A gland in the male reproductive system. The prostate surrounds the part of the urethra (the tube that empties the bladder) just below the bladder, and produces a fluid that forms part of the semen.

Cancer that forms in tissues of the prostate (a gland in the male reproductive system found below the bladder and in front of the rectum). Prostate cancer usually occurs in older men.

A substance produced by the prostate. It may be found in higher levels in the blood of men who have prostate cancer, benign prostatic hyperplasia, infection or inflammation of the prostate. Also called prostate-specific antigen.

A hormone made mainly in the testes (part of the male reproductive system). It is needed to develop and maintain male sex characteristics, such as facial hair, deep voice, and muscle growth. Testosterone may also be made in the laboratory and is used to treat certain medical conditions.

A medical system that has been used for thousands of years to prevent, diagnose, and treat disease. It is based on the belief that qi (the body's vital energy) flows along 20 meridians (channels) throughout the body and keeps a person’s spiritual, emotional, mental, and physical health in balance. Traditional Chinese medicine aims to restore the body’s balance and harmony between the natural opposing forces of yin and yang, which can block qi and cause disease. Traditional Chinese medicine includes acupuncture, diet, herbal therapy, meditation, physical exercise, and massage. Also called Oriental medicine and TCM.