This paper describes the antinociceptive action of 13,118-binaringenin (GB-1a), a biflavonoid isolated from Clusia columnaris and present in several plants of the family Guttiferae, in a writhing test and a formalin test. It was found that it exhibits potent and dose-related antinociceptive action in both experimental models, with ID50 values of 22 mumol/kg against the writhing test and 28 mumol/kg against the second phase of the formalin test. It was more potent than some well-known analgesic drugs used as reference. Based on a hot-plate test its mechanism of action seems to be unrelated with the opioid receptors.