Chaparral Has a History of Medicinal Use and a Controversial Place in Cancer Therapy.
By Safiyyah Bazemore
Chaparral (Larrea tridentata) is a low-growing evergreen shrub native to the deserts of North America’s southwest and central Mexico. Also known as creosote bush, greasewood, and gobernadora, the plant is in the Zygophyllaceae family.
To people who live in the region, the smell of chaparral is unmistakable, because it is recognized as a precursor to rainfall. Volatile oils are released in abundance right before rain and linger long afterward, thanks to chaparral’s resinous leaves.
The name Chaparral can also refer to a plant community in California, characterized by dry summers, mild winters, and drought-tolerant plants, but Larrea tridentata does not commonly grow in the chaparral biome.
The leaves of chaparral have traditionally been utilized by Native Americans to address a variety of ailments, and the plant was even an official medicinal substance listed in the U.S. Pharmacopeia for 100 years.
Today, chaparral’s medicinal use is steeped in controversy largely as a result of conflicting studies concerning the plant’s actions on the liver.
Traditional Use and Benefits
Populations native to the American Southwest have a long history of medicinal chaparral use. The Maricopa, Pima, Shoshone, and Papago tribes used the plant both internally and externally, relying on its leaves to assist with symptoms related to diabetes, arthritis, menstrual disorders, stomach complaints, chickenpox, influenza, and cancer, and several other ailments. Chaparral was a panacea for the region’s inhabitants, unique in its ability to help with a broad range of health conditions.
Common preparations of chaparral both past and present include heating sap from its branches to apply on toothaches, making a strong tea from its leaves, macerating the plant to use as a poultice applied to distressed body parts, or infusing it in an oil or salve for external use. Today, chaparral’s leaves and stems are often sold cut and dried, as tinctured extracts, or in capsule form. Its sheer abundance in the U.S. southwest makes it a readily accessible plant to wildcraft.
Chaparral and Cancer
Chaparral has blood purifying properties, and in the body it functions as an antiseptic, diuretic, expectorant, alterative, and a whole-system tonic. Notably, chaparral is a powerful antioxidant due to its high content of nordihydroguaiaretic acid (NDGA), a compound known for its potential antiviral, anti-inflammatory, and anti-tumour effects.
The resin coating chaparral’s leaves is largely composed of lignans, bioactive phenolic compounds common in high-fibre plants. NDGA is chaparral’s main lignan, as it comprises up to 50% of its leaf resin. Studies have suggested that NDGA’s high antioxidant properties may inhibit enzymes that promote tumour growth.
There have been reports of successful use of chaparral in shrinking certain tumours and the regression of malignant melanomas after ingesting a tea made from its leaves, but extensive clinical data into chaparral’s anticancer properties is limited. Despite its significant usage by indigenous populations for centuries and its popularity as a 20th-century alternative cancer therapy, the use of chaparral is discouraged by many medical professionals due to questions of the plant’s safety.
Controversy in the Creosote Bush
The controversy behind chaparral centres on observations of potential hepatotoxicity resulting from its internal use. Some entities outright do not recommend ingesting chaparral in any form, as some studies have found evidence of liver damage in patients who had consumed the herb. In addition, the United States Food and Drug Administration removed chaparral from its Generally Recognized as Safe (GRAS) list in the 1950s (Drugs.com).
Other studies into chaparral’s safety and efficacy as a natural remedy have determined that chaparral is non-harming to the liver in relatively low doses. Researchers have also discovered that when NDGA, chaparral’s main constituent, is O-methylated, the toxicity is virtually erased.
Generally, herbalists agree that taking chaparral is safe in low doses over short periods of time, but most recommend avoiding the herb if one has a pre-existing liver or kidney condition (7song.com). Some also suggest only the topical application of chaparral in salves, baths, or poultices—refraining from internal use altogether.
The Bottom Line
Though a controversial plant, chaparral’s medicinal usage throughout history and into modernity is significant. Its use in practice to address a wide range of health issues and its anti-cancer potential warrants more thorough clinical study.
This content is not intended to be a substitute for professional medical advice, diagnosis, or treatment. We advise readers to always seek the advice of a physician or other qualified health provider with any questions you may have regarding a medical condition.