Yerba Santa is a plant that was historically used by Native Americans for a wide variety of ailments from bruises to muscle soreness and its effects on the respiratory system.
What is Yerba Santa?
Yerba Santa (Eriodictyon) refers to a genus of shrubs belonging to the family of Boraginaceae which is native to North America. It is commonly found in the southwestern region of the United States in California, Oregon, and Northern New Mexico where it flourishes in climates with hot, dry summers and mild winters. Some species of the Eriodictyon genus can be found as far as the Midwest United States, with a few in the Northeastern region of the United States.
“Yerba Santa” is a Spanish phrase meaning “holy herb” or “holy weed,” but the species name Eriodictyon is derived from the Greek phrase “woolly net” because of the fuzzy texture of the underside of the leaves. It is also known by the names Mountain Balm, Gum Plant, Bear’s Weed, Consumptive Weed, and Sacred Herb. [1, 2, 3, 4]
What is the history of Yerba Santa?
Yerba Santa loosely refers to many different variations of the Eriodictyon species. The Native American tribes Salinan, Miwok, Ohlone, Yokuts, and Pomo have used Yerba Santa for many thousands of years. It was encountered by the Spanish missionaries who came to California and legend has it that it was introduced to Spanish priests at the Mission San Antonio de Padua from the Salinan tribe. It was so revered for its medicinal properties and ability to treat respiratory illnesses by the Spanish missionaries that they deemed it a “holy herb”. By 1875, Yerba Santa was included in the Eclectic Medical Journal, and it was listed in the Pharmacopoeia of the United States in 1894. Yerba Santa was traditionally brewed into a tea, eaten, or used as poultice after it has been harvested in the fall when the leaves are at their stickiest. All of the plant was utilized including the leaves, flowers, and stems. [4, 5]
What are the traditional uses of Yerba Santa?
- The Kawaiisu tribe drank tea made from Yerba Santa to treat gonorrhea
- The Salinan tribe made an infusion from the leaves for a salve for the eyes
- The Ohlone tribe used the leaves for woven skirts and aprons
- The Spanish missionaries at San Antonio Mission chewed or smoked the leaves to relive coughs, asthma, colds, stomachaches, headaches, joint pain, and to purify the blood. They also applied the sticky, mashed leaves to skin wounds and sore muscles. Yerba Santa was specifically used to treat rheumatism by burning the branches and leaves in steam baths. 
What are the most common types of Yerba Santa?
Yerba Santa is a term that is used loosely, and many people associate the term with only the Californian Yerba Santa (Eriodictyon californicum), but there 16 species found in California. 
Varieties found in California, United States:
- Eriodictyon californicum
- “California Yerba Santa”
- Lavender to white flowers that bloom May-July
- Leaves were used medicinally by 14 Native American tribes
- Grows from Oregon, down the Sierra Nevada mountain range in California
- Grows at elevations below 6,000 ft
- Eriodictyon angustifolium
- “Narrow Leaf yerba santa”
- White flowers with five petals
- Blooms June or July
- Native to pinyon-juniper Woodland habitats
- Grows in the Mojave Desert in California, Baja California, Nevada, and Utah 
- Eriodictyon crassifolium
- “Thick Leaf yerba santa”
- Lavender-colored flowers that bloom April-June
- Grows at elevations below 5,000 ft
- Eriodictyon crassifolium var. crassifolium
- Eriodictyon crassifolium var. nigrescens
- “Bicolored yerba santa”
- Eriodictyon trichocalyx
- “Hairy yerba santa”
- Flowers April-July
- Very short, hairy leaves
- Eriodictyon trichocalyx var. lanatum
- “San Diego Yerba Santa”
- Eriodictyon trichocalyx var. trichocalyx
- Eriodictyon trichocalyx var. lanatum
- Eriodictyon tomentosum
- “Wooly Yerba Santa”
- The white wooly hairs make the bush appear silver 
- Leaves are covered by white felt hairs
- Flowers June & July
- Grows at elevations below 4,500 ft 
- Eriodyctyon altissimum
- “Indian Knob mountainbalm
- Native to San Luis Obispo County, California
- Narrow leaves 
- Eriodictyon capitatum
- “Lompoc yerba santa”
- Rare, endangered species
- Native to western Santa Barbara County
- Eriodictyon lobii
- Native to Sierra Nevada Mountain Range and southern Cascade Mountain Range in California, Nevada, and Oregon
- Eriodictyon parryi
- Native to southern California and Baja California in the Transverse Ranges
- Eriodictyon traskiae
- “Pacific yerba santa”
- White wooly hairs make the shrub appear grey/green
- Oval leaves
- Eriodictyon traskiae ssp. smithii
- “Smith’s yerba santa”
- Eriodictyon traskiae ssp. traskiae
- “Trask’s yerba santa” 
- Eriodictyon traskiae ssp. smithii
What is Yerba Santa made of?
The flavonoids of yerba santa are:
- Flavanones (listed from highest concentration to least):
Found in smaller quantities:
- Kaempferol 3-O-glucoside
- Quercitin 3-O-glucoside 
Safety and Side Effects of Yerba Santa
Yerba Santa has been used a bitter flavoring additive to foods and is safe in small amounts. Though it has been used traditionally for thousands of years, Yerba Santa hasn’t been the subject of many clinical studies, and data on its safety is relatively scarce.
As an expectorant, it is a possibility that using Yerba Santa to help clear congestion can be so efficient that it may over-dry nasal and lung passages. This is common with all expectorants, including pharmaceutical and over-the-counter expectorants.
A theorized medication interaction may occur between Yerba Santa and Lithium. A moderate interaction may occur which may reduce excretion due to Yerba Santa’s diuretic properties and this may increase levels of the medication Lithium. 
- “Eriodictyon Californicum.” Wikipedia, en.wikipedia.org/wiki/Eriodictyon_californicum#Taxonomy.
- “Plant of the Week: Yerba Santa.” www.fs.fed.us/wildflowers/plant-of-the-week/eriodictyon_sp.shtml.
- Kaminiski, Patricia, and Richard Katz. “Yerba Santa.” www.flowersociety.org/Yerba_About.htm.
- “California Yerba Santa.” USDA NRCS, plants.usda.gov/plantguide/pdf/cs_erca6.pdf.
- “Yerba Santa.” www.indianmirror.com/ayurveda/yerba-santa.html.
- “California Native Plant Society.” calscape.org/loc-California/eriodictyon(all)/ord-species/allplants/vw-list?view_style=list.
- “Eriodictyon Angustifolium.” Wikipedia, en.wikipedia.org/wiki/Eriodictyon_angustifolium.
- Spjut, Richard W. “Eriodictyon.” Aug. 2006, www.worldbotanical.com/eriodictyon.htm.
- “Yerba Santa.” Foods, Herbs & Supplements. https://naturalmedicines.therapeuticresearch.com/databases/food,-herbs-supplements/professional.aspx?productid=393.
- “Yerba Santa (Eriodictyon Californicum).” www.sigmaaldrich.com/life-science/nutrition-research/learning-center/plant-profiler/eriodictyon-californicum.html.
- “Flavonoid Aglycones from Eriodictyon Californicum Resin and Their Implications for Herbivory and UV Screening.” Biochemical Systematics and Ecology, vol. 11, no. 3, Dec. 1983, pp. 211–215., 10.1016/0305-1978(83)90056-X.
- Ahmed, MS, et al. “A Weakly Antimalarial Biflavanone from Rhus Retinorrhoea.” Phytochemistry, vol. 58, no. 4, Oct. 2001, pp. 599–602., www.ncbi.nlm.nih.gov/pubmed/11576606.
- Matsuo, M, et al. “Cytotoxicity of Flavonoids toward Cultured Normal Human Cells.” Bio Pharm Bull., vol. 28, no. 2, Feb. 2005, pp. 253–9., www.ncbi.nlm.nih.gov/pubmed/15684479.