Although a number of different mistletoe extracts have been used in human studies, the reported side effects have generally been minimal and not life threatening. Common side effects include soreness and inflammation at injection sites, headache, fever, and chills. Reviewed in [1-3] A few cases of severe allergic reactions, including anaphylactic shock, have been reported.[2]

In contrast, mistletoe plants and berries are considered poisonous. Seizures, vomiting, and death have been reported following ingestion of these substances. Reviewed in [1,4] The severity of the toxic effects associated with mistletoe ingestion may depend on the amount consumed and the type of mistletoe plant. Reviewed in [4]

References

1. Kaegi E: Unconventional therapies for cancer: 3. Iscador. Task Force on Alternative Therapies of the Canadian Breast Cancer Research Initiative. CMAJ 158 (9): 1157-9, 1998.  [PUBMED Abstract]
   
   
2. Hutt N, Kopferschmitt-Kubler M, Cabalion J, et al.: Anaphylactic reactions after therapeutic injection of mistletoe (Viscum album L.). Allergol Immunopathol (Madr) 29 (5): 201-3, 2001 Sep-Oct.  [PUBMED Abstract]
   
   
3. Stauder H, Kreuser ED: Mistletoe extracts standardised in terms of mistletoe lectins (ML I) in oncology: current state of clinical research. Onkologie 25 (4): 374-80, 2002.  [PUBMED Abstract]
   
   
4. Hall AH, Spoerke DG, Rumack BH: Assessing mistletoe toxicity. Ann Emerg Med 15 (11): 1320-3, 1986.  [PUBMED Abstract]
   
   

Glossary Terms

A severe and sometimes life-threatening immune system reaction to an antigen that a person has been previously exposed to. The reaction may include itchy skin, edema, collapsed blood vessels, fainting, difficulty in breathing, and death.

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 trial.

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

Redness, swelling, pain, and/or a feeling of heat in an area of the body. This is a protective reaction to injury, disease, or irritation of the tissues.

Taking into the body by mouth.

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.

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.

Having to do with poison or something harmful to the body. Toxic substances usually cause unwanted side effects.

To eject some or all of the contents of the stomach through the mouth.