National Cancer Institute
at the National Institutes of Health
- Mistletoe is a semiparasitic plant that grows on several types of common trees such as apple, oak, pine, and elm. Mistletoe extract has been used since ancient times to treat many ailments (see Question 1).
- Mistletoe is one of the most widely studied complementary and alternative medicine therapies in people with cancer. In certain European countries, preparations made from European mistletoe are among the most prescribed drugs for patients with cancer (see Question 1).
- Mistletoe extract has been shown to kill cancer cells in the laboratory and to affect the immune system. However, there is limited evidence that mistletoe's effects on the immune system help the body fight cancer (see Question 2 and Question 3).
- Mistletoe extracts are usually given by injection under the skin or, less often, into a vein, into the pleural cavity, or into the tumor. (see Question 4).
- Animal studies have suggested that mistletoe may be useful in decreasing the side effects of standard anticancer therapy, such as chemotherapy and radiation (see Question 5).
- Several human studies using mistletoe to treat cancer have been done since the early 1960s, but major weaknesses in many of these have raised doubts about their findings (see Question 6).
- Very few harmful side effects have been reported from the use of mistletoe extract (see Question 7).
- The U.S. Food and Drug Administration (FDA) has not approved mistletoe as a treatment for cancer or any other medical condition (see Question 8).
- The FDA does not allow injectable mistletoe to be imported, sold, or used except for clinical research (see Question 8).