title: The safety of low-dose Larrea tridentata (DC) Coville (creosote bush or chaparral): a retrospective clinical study.
abstract: OBJECTIVE
  To determine whether internal use of low doses of Larrea tridentata tincture or topical applications of this traditional herbal medicine are safe.
  
  
  METHODS
  Retrospective review of all people prescribed Larrea for internal or for topical use over a 22-month period.
  
  
  METHODS
  A general naturopathic practice in Sedona, Arizona.
  
  
  METHODS
  Thirteen patients were identified for whom Larrea tincture for internal use was prescribed. An additional 20 female and 3 male patients were identified for whom an extract of Larrea in Ricinus communis (castor) oil for topical use was prescribed. No patient had any history of liver disease.
  
  
  METHODS
  Larrea was prescribed as part of the usual care of each patient. In all cases it was given as either part of a complex herbal formula individualized for each patient containing less than 10% Larrea tincture or as an extract in Ricinus oil for topical use.
  
  
  METHODS
  Serum liver enzyme levels as well as blood urea nitrogen and creatinine levels, glucose levels, electrolytes, bilirubin levels, iron levels, ferritin levels, lipid levels, and complete blood count (CBC) were available for analysis in four patients; general clinical history and physical examination findings were relied on in all other cases.
  
  
  RESULTS
  The four patients with complete before and after blood chemistry panels and CBC had no indication of liver damage from use of Larrea. This included one patient who was taking medications with significant potential for hepatotoxicity. No patient in the study, whether using Larrea for short term or long, internally or externally, showed any sign of organ damage during the period of follow-up.
  
  
  CONCLUSIONS
  Relatively small intakes of Larrea tincture, or topical application of extracts in Ricinus oil, are safe when prescribed by a clinically trained botanical prescriber. Larrea should be used with caution in persons with a history of previous, or current, liver disease. It may be preferable to avoid the use of Larrea capsules because they have been associated with potentially dangerous overdosing.
authors.affiliation: Naturopathic Family Health Care, Sedona, AZ, USA.
authors.forename: S
authors.initials: S
authors.lastname: Heron
authors.forename: E
authors.initials: E
authors.lastname: Yarnell
mesh_terms: D000279:Administration, Cutaneous; D000284:Administration, Oral; D005260:Female; D006705:Homeopathy; D006801:Humans; D006967:Hypersensitivity / Q000517:prevention & control*; D008099:Liver / Q000187:drug effects*; D008297:Male; D008875:Middle Aged; D008517:Phytotherapy; D010936:Plant Extracts / Q000009:adverse effects; D010938:Plant Oils / Q000009:adverse effects; D010946:Plants, Medicinal; D010947:Plants, Toxic; D012189:Retrospective Studies; D012278:Ricinus / Q000009:adverse effects*; D019685:Rosales
chemical_list: D010936:Plant Extracts; D010938:Plant Oils