This work describes the phytochemical analysis and analgesic activity of a non polar fraction obtained from Adiantum cuneatum grown in Brazil. The results showed that the hexane fraction as well as two pure compounds, identified as filicene (1) and filicenal (2), given intraperitoneally, exhibited potent analgesic activity when evaluated in two models of pain in mice, writhing test and formalin-induced pain. Compound 1 presented a calculated ID50 value of 19.5 micromol/kg body weight, when

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... ated in writhing test, being about 7-fold more active than some reference drugs, like as acetyl salicylic acid and acetaminophen. It also inhibited both phases (neurogenic and inflammatory) of the formalin test at 10 mg/kg (24 micromol/kg). The chemical composition of the plant grown in Brazil is similar to that grown in other countries. The results confirm and justify the popular use of this plant for the treatment of dolorous processes.