• Mistletoe is a plant that grows on several types of common trees such as apple, oak, and elm, and has been used since ancient times to treat many ailments (see Question 1 ¹).



• Mistletoe extract has been shown to kill cancer cells in the laboratory and to affect the immune system. However, there is no evidence that mistletoe's effects on the immune system help the body fight cancer (see Question 2 ² and Question 3 ³).



• Mistletoe extracts are usually given by injection under the skin or, less often, into a vein or into the pleural cavity (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 ⁴).



• More than 30 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 ⁵).



• Very few bad side effects have been reported from the use of mistletoe extract, though mistletoe plants and berries are poisonous to humans (see Question 7 ⁶).



• 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 ⁷).



• The FDA does not allow injectable mistletoe to be imported, sold, or used except for clinical research (see Question 8 ⁷).

Glossary Terms

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.

Treatment with drugs that kill cancer cells.

Having to do with the examination and treatment of patients.

In medicine, a preparation of a substance obtained from plants, animals, or bacteria and used as a drug or in drugs.

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.

The complex group of organs and cells that defends the body against infections and other diseases.

Use of a syringe and needle to push fluids or drugs into the body; often called a "shot."

A semiparasitic plant that grows on some types of trees. Mistletoe extracts are being studied as treatments for cancer.

The space enclosed by the pleura, which is a thin layer of tissue that covers the lungs and lines the interior wall of the chest cavity.

Energy released in the form of particle or electromagnetic waves. Common sources of radiation include radon gas, cosmic rays from outer space, medical x-rays, and energy given off by a radioisotope (unstable form of a chemical element that releases radiation as it breaks down and becomes more stable).

A problem that occurs when treatment affects healthy tissues or organs. Some common side effects of cancer treatment are fatigue, pain, nausea, vomiting, decreased blood cell counts, hair loss, and mouth sores.

In medicine, treatment that experts agree is appropriate, accepted, and widely used. Health care providers are obligated to provide patients with standard therapy. Also called best practice and standard of care.

Treatment.

A blood vessel that carries blood to the heart from tissues and organs in the body.