Known interactions

No interactions found.

What we now about Dagger Plant

Scientific Name: Yucca

Other Names: Adam's Needle, Bear Grass, Dagger Plant, Joshua Tree, Mohave Yucca, Our-Lord's-Candle, Soapweed, Spanish Bayonet, Yucca species

Who is this for?

Although no well-controlled human studies have been conducted to verify them, a few animal studies and case reports suggest a limited role for oral yucca in treating both cardiovascular and high cholesterol levels. First, yucca contains a proven antioxidant, a chemical known as resveratrol. Antioxidants are thought to protect body cells from damage caused by a chemical process called oxidation. Oxygen free radicals, natural chemicals produced by oxidation, are known to be involved in the development of several conditions including heart diseases. By limiting oxidation, resveratrol and other antioxidants may help prevent damage to blood vessels and other changes that may contribute to the development of heart disease. In addition, yucca contains a high percentage of saponins, chemicals that dissolve in both water and oil. In the stomach and intestines, some saponins may fasten onto cholesterol particles in the blood, thereby preventing cholesterol absorption by the body and promoting its elimination. Although saponins from yucca have not been studied specifically, saponins from other plant sources also attach to bile, effectively removing it from circulation. The body then has to use some dietary or stored cholesterol to make more bile, further reducing the amount of cholesterol that stays in the blood.

Traditionally, yucca has been used orally to treat arthritis and related ailments such as bursitis and gout. Although little research supports the specific use of yucca for treating arthritis, some researchers believe that saponins generally may interfere with the production of a chemical that keeps the body from making new cartilage for joints. Saponins may also have anti-inflammatory effects. In one small study conducted nearly 30 years ago, oral yucca seemed to show some mild relief of pain, stiffness, and swelling among some of the participants who took daily doses of various yucca extracts for periods of up to 15 months. However, the lengths of time that the participants took yucca, the yucca products they used, and the dosages they took all varied greatly. Many participants also took more conventional remedies for arthritis, such as aspirin, in addition to yucca during the study period. Results of this study have not been verified by more recent controlled research, so they cannot be viewed as conclusive.

As an antioxidant, yucca may also have potential as an anticancer, antiviral, and immune-stimulating agent. The antioxidant effects of yucca may also protect the liver from some of the damage caused by certain drugs or chemicals or by chronic alcohol abuse. Some case reports may also show that yucca has potential to prevent or lessen the severity of migraine headaches. All these possible effects need further study to prove or disprove them.

Topical yucca is thought to help stop minor bleeding from cuts and scrapes. Because the saponins in it may be anti-inflammatory, yucca may also help to relieve itching and swelling from insect bites, sunburn, and other minor skin injuries. Reportedly, yucca and other saponin-containing herbal products have been applied to the scalp for treating dandruff and to the skin for treating eczema and psoriasis. None of these possible uses have been proved by study results. Yucca’s soapy consistency does, however, make it a good soap or shampoo substitute.

When should I be careful taking it?

No cases of human toxicity from yucca have been reported in medical literature. However, the roots of yucca species contain chemicals called saponins, which may be used in pesticides because they are poisonous to insects and other small creatures. Saponins are not absorbed from the gastrointestinal tract in humans; therefore, they do not appear to be toxic to humans when taken by mouth or used topically. If injected into the blood, however, saponins can dissolve red blood cells.

What side effects should I watch for?

Ingesting several times the recommended daily dose of oral yucca could result in severe diarrhea.

Individuals who take yucca orally have also reported:

  • Bitter taste in the mouth
  • Irritated mouth or throat
  • Nausea
  • Upset stomach
  • Vomiting

Applied topically, yucca preparations possibly may further irritate open scrapes or cuts.

What interactions should I watch for?

No interactions between yucca and prescription drugs, non-prescription drugs, other herbal products, or foods have been reported. However, because few reliable studies of yucca have been conducted in humans, its possible interactions are not understood completely.

Some interactions between herbal products and medications can be more severe than others. The best way for you to avoid harmful interactions is to tell your doctor and/or pharmacist what medications you are currently taking, including any over-the-counter products, vitamins, and herbals.

Should I take it?

Yucca used in medicine comes from the leaves, flower stalks, and roots of over 30 species of related shrubs or small trees that grow primarily in desert areas of the American southwest and other dry areas of North America. Some yucca species, however, have adapted for cooler, wetter climates such as those in the central plains states. The large, fleshy, sword-shaped leaves of most yuccas stay green all year and their clusters of white or yellow-green flowers bloom on tall central spikes. Some species of yucca have flowers that smell stronger at night so they attract a specific kind of moth that pollinates the plants. Yuccas all contain chemicals called saponins that give them a bitter taste and a soapy feel. Because saponins are toxic to many small animals and insects, yucca plants are not usually attacked by garden pests. In general, the roots contain more saponins than the leaves and stalks do, so yucca roots are not used as much for medicine.

Native Americans used yucca stems for fibers to make baskets, clothing, or mats; its roots for soap; its fruits for juice; and its leaves, flowers, fruits, and seedpods for food. Cooking yucca breaks down the saponins in it, so food source of yucca may not offer the medicinal advantages thought to be associated with it. The roots of some types of yucca are used to make dyes. Yucca extract is FDA-approved for use as a foaming agent in foods such as beer and soft drinks. It is also used as an additive in flavorings, foods, pet foods, shampoo, and soap.

Dosage and Administration

Note: Uninterrupted oral use of yucca is not recommended for periods longer than 3 months at a time, due to the chance that fat-soluble vitamins may be depleted as saponins inactivate fats in the gastrointestinal system.

As a dietary supplement, yucca is available as capsules, tablets, or liquid to take by mouth. Doses for commercially available oral forms, which usually come in strengths between 380 mg and 490 mg, are generally taken twice a day and based on body weight. For a tea, 7 to 8 mg (about a quarter of an ounce) of dried yucca roots or stalks can be boiled in 16 ounces of water for about 15 minutes. After the resulting liquid is strained to remove solid particles, it may be consumed as a tea – usually divided into three or four cups.

Yucca is also available in liquids, gels, or creams to apply topically as needed. Cooled yucca tea may be used as a wash, and fresh yucca roots may be boiled until soft and then mixed with petroleum jelly for an ointment.


Today, oral yucca is thought to have some mild effectiveness in preventing and treating heart conditions and high cholesterol levels. Some unconfirmed evidence suggests it may help relieve the symptoms of arthritis. It may also provide antioxidant benefits in several different conditions. Topical forms of yucca can help relieve inflammation and minor skin irritation.


No major risks have been associated with the oral or topical use of yucca. The saponins in it can dissolve red blood cells, however, if it is injected into the blood.

Side Effects

The main side effects reported from oral yucca are stomach upset and irritation of mucous membranes. Applied to broken or severely irritated skin, topical yucca can cause more irritation.


No interactions have been reported between yucca and prescription drugs, non-prescription drugs, other herbal products, or foods.


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(Note: The above information is not intended to replace the advice of your physician, pharmacist, or other healthcare professional. It is not meant to indicate that the use of the product is safe, appropriate, or effective for you.)

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