Historical or traditional use (may or may not be supported by scientific studies): Native Americans used the soapy leaves from yucca for numerous conditions. Poultices or baths were used for skin sores and other diseases as well as for sprains. Inflammation of all sorts, including joint inflammations and bleeding, were also treated with yucca. It is also reported that Native Americans washed their hair with yucca to fight dandruff and hair loss.

Research continues on the virtues of this herb in combating certain forms cancer. It has been shown effective in inhibiting almost completely sarcoma 180 and Ehrlich carcinoma, according to the prestigious Sloan-Kettering Cancer Research Institute. According to Oncology (22:57), extract of Yucca strongly inhibited Lewis lung mouse tumor and the Friend virus leukemia in mice by some 70%.

Doctors Bernard Bellew and Robert Bingham conducted studies at the National Arthritis Medical Clinic with 101 arthritic patients, giving half Yucca tablets and the other half placebos (look-alikes). Those receiving four Yucca tablets, 61% reported feeling less pain, stiffness and swelling in their arthritis than those on the placebo.

A double-blind trial indicated a saponin extract of Yucca demonstrated a positive therapeutic effect on osteoarthritis, according to J. Applied Nutrition.

Active constituents: The saponins from yucca are the major constituents in the plant. They have both a water- and fat-soluble end and therefore act like soap. One preliminary trial reportedly found benefit for patients with osteoarthritis and rheumatoid arthritis.1 The authors of the study speculate that yucca saponins may block release of toxins from the intestines that inhibit normal formation of cartilage. This has yet to be proven in human pharmacological studies. An extract of one species of yucca has been found to fight melanoma cells in test tube studies.2 Clinical trials are lacking to prove whether yucca may be useful for treating cancer in humans.

How much is usually taken? Although the exact dosage of yucca for arthritis is unclear, some sources suggest up to 2 grams of yucca root in capsules per day.3 Alternatively, 1/4 ounce (7 grams) of the root can be boiled in a pint (500 ml) of water for 15 minutes. Three to five (750–1250) cups of this tea may be taken each day.4

Are there any side effects or interactions? Yucca can cause loose stools at higher amounts (several times higher than the recommended amounts).5 Yucca and other saponins can cause red blood cells to burst (known as “hemolysis”) in test tubes. The level to which this occurs when the saponins are taken by mouth, if it occurs at all, is unknown. However, yucca is approved for use in foods as a foaming agent (particularly in root beer). Since there have been no reports of problems with hemolysis in root beer drinkers, yucca herbal supplements are believed to be generally safe.6 Use of yucca for more than three months consecutively is not recommended as it may interfere with the absorption of fat-soluble vitamins.7

At the time of writing, there were no well-known drug interactions with yucca.

• Recommended Dosage

Capsule: Four capsules twice daily.

References:
1. Bingham R, Bellew BA, Bellew JG., Yucca plant saponin in the management of arthritis. J Applied Nutrition 1975;27:45–50.

2. Foster S, Duke JA., A Field Guide to Medicinal Plants: Eastern and Central North America. Boston: Houghton Mifflin Co., 1990, 18, 228.

3. Foster S., 101 Medicinal Herbs. Loveland, CO: Interweave Press, 1998, 216–7.

4-5-7. Moore M., Medicinal Plants of the Desert and Canyon West. Santa Fe: Museum of New Mexico Press, 1989, 134–5.

6. McGuffin M, Hobbs C, Upton R, Goldberg A., American Herbal Products Association’s Botanical Safety Handbook. Boca Raton, FL: CRC Press, 1997, 124.