Medicinal use of olive leaf extract goes as far back as the mid 1800s, when it was as used as a treatment for malaria. A variety of active compounds have been identified in olive leaf and scientific evidence of their usefulness as antimicrobial immune-boosting agents in the treatment of some forms of cancer shows promising results. Check with your doctor about using olive leaf extract to treat a medical condition.

Broad Spectrum Effects

Olive leaf extract improves your white blood cells' ability to kill cancer cells and carry them away to be eliminated from your body, according to Russel L. Blaylock, M.D., in his book, "Natural Strategies for Cancer Patients." Olive leaf has broad spectrum germ-killing ability, with ability to disable viruses, fungi and rickettsia -- bacteria that cause diseases carried by ticks, fleas and lice. This herbal remedy is safe and non-toxic, says Blaylock.

Immune Strenghtening

A component of the immune system known as T helper 1 cells is strengthened by olive leaf extract, says Michael J. Gonzalez, D.Sc., Ph.D., author of the book,"I Have Cancer: What Should I Do?: Your Orthomolecular Guide for Cancer Management." T cells fight viruses, bacteria and cancer. Olive leaf extract also helps your body to be more efficient at detoxification, decreasing your risk for developing cancer and taking the burden off an already stressed immune system, if you have cancer.

Leukemia

Researchers at the Department of Biology, University of Balamand, Lebanon, reported anti-leukemia effects of olive leaf extract in a study published in the March 2011 issue of the journal "Plant Foods in Human Nutrition." In the tissue culture study, olive leaf extract inhibited leukemia by inducing apoptosis -- programmed cell death -- in the cancer cells.

Breast Cancer

Breast cancer may respond well to treatment with olive leaf extract, according to research published in the January 2011 issue of the journal "Food and Chemical Toxicology." An extract from olive leaf, called hydroxytyrosol -- a polyphenol antioxidant compound -- arrested growth in a tissue culture of human breast cancer cells at an early stage in the growth cycle. Researchers are optimistic about the future uses of olive leaf extract as a cancer-preventive.

Skin Cancer

Olive leaf extract may offer protection against some forms of skin cancer, according to a study published in the April 2011 issue of the "International Journal of Cancer." In the tissue culture study, olive leaf extract showed strong anti-cancer activity against melanoma, an aggressive form of cancer that is resistant to immune and chemotherapy effects. Researchers caution that olive leaf extract used in combination with conventional cancer drugs resulted in both increased and, in some case, inhibitory effects of the drugs.