RESUMEN
One of the Brazilian arnicas, Solidago chilensis Meyen, is a species of the family Asteraceae. This plant is known by this common name because it shares very similar organoleptic properties with the genus Arnica L., also within the family Asteraceae, that comprises approximately 30 European species of perennial, herbaceous plants. The effectiveness of a fluid extract of S. chilensis used externally for treating lumbago was examined in placebo-controlled double-blind clinical pharmacological studies. Two daily skin applications of a gel containing a 5% extract in glycol were administered for 15 days to ten volunteers in a placebo group and to an equal number in a test group. Statistical analyses of the results demonstrated a significant reduction in the perception of pain and a significant increase in the flexibility of patients in the test group as compared with those receiving only the placebo.