To the Editor.
—For everyone not born in California, it is difficult to identify the plant described by Dr Gordon and colleagues.1 Together with the two other vernacular names creosote bush and greasewood cited by the authors, I found no less than four different plants in Webster's2 and in The Plant Book.3Larrea divaricata subsp tridentata (Zygophyllaceae), also named Larrea tridentata or Covillea tridentata for the creosote bush. Moreover, for the term chaparral pea, I found Pickeringia montana (Leguminosae), and for the term greasewood, I found Sacrobatus vermiculatus (Chenopodiaceae). The active ingredient of chaparral as described by Gordon et al is nordihydroguaiaretic acid (NDGA), which occurs in many plants. Therefore, this substance is not the best key to finding the exact botanical name of chaparral. I hope, however, that L divaricata subsp tridentata was the cause of the liver injury of the patient in the article by