Horsetail Health Article

Precautions

Pregnant or nursing women and people with severe kidney or liver disease should consult their health practitioner before using horsetail. People with high blood pressure or heart problems should not take horsetail. Horsetail contains low levels of nicotine and may not be safe for young children. Horsetail shouldn't be taken internally for more than three days, and people should not take more than the normal dosage. Long-term use or high doses of horsetail have caused irreversible kidney damage due to too much silica. It is best to follow dosage guidelines and use properly harvested horsetail since the older shoots are higher in silica.

Commercial preparations that are processed at high temperatures are recommended since the heat destroys a potentially harmful enzyme, thiaminase, found in crude horsetail.

When horsetail is gathered for medicinal use, plants with brown spots aren't collected. Brown spots may indicate the presence of a toxic fungus. Horsetail that grows near an industrial or waste site or in heavily fertilized areas should not be harvested since it can pick up nitrates and selenium from the soil. The correct species of horsetail should be collected. Marsh horsetail (E. palustre) is poisonous.

Side effects

Mild side effects include diarrhea, upset stomach, and increased urination.

Severe side effects that may require medical attention are kidney pain, lower back pain, pain while urinating, nausea, or vomiting. These symptoms may signal kidney damage. Heart palpitations can occur if horsetail is overused. If this happens, immediate medical attention is required.

Interactions

People taking digitalis-type drugs should consult their health practitioner before taking horsetail.

BOOKS

American Herb Association. Complete Book of Herbs. Illinois: Publications International, Ltd., 1997.

Fischer-Rizzi, Susanne. Medicine of the Earth. Cambridge, MA: Rudra Press, 1996.

Jennifer Wurges