The present study examined the effect of peroral administration of bis(phenylimidazoselenazolyl) diselenide (BPIS) in thermal and chemical models of pain in mice. The involvement of the opioid system in the BPIS antinociceptive effect was also examined, as well as potential nonspecific disturbances in locomotor activity or signs of acute toxicity. BPIS (25-100 mg/kg) induced an increase in tail-immersion response latency and this effect was significant at pretreatment times of 15 min to 4 h, but not at 8 h. The hot-plate response latency was also increased by the administration of BPIS (25-100 mg/kg). BPIS, at doses of 25 and 50 mg/kg, inhibited writhing behaviour caused by an intraperitoneal acetic acid injection. Both early and late phases of nociception caused by the intraperitoneal formalin injection were inhibited by BPIS (10-50 mg/kg). BPIS, administered at doses equal to or greater than 10 and 25 mg/kg, reduced nociception produced by an intraperitoneal injection of capsaicin and glutamate, respectively. The antinociceptive effect of BPIS, when assessed in the tail-immersion test, was not abolished by naloxone. BPIS (10-50 mg/kg) did not alter alanine transaminase and aspartate transaminase activities (parameters of hepatic function) or urea and creatinine levels (parameters of renal function), and did not affect motor activity in the open-field test. The results indicate that BPIS produced an antinociceptive action without causing motor disturbances or toxicity. Moreover, opioidergic mechanisms seem not to be involved in the antinociceptive action of BPIS. Here, BPIS has been found to be a novel organoselenium compound with antinociceptive properties; however, more studies are required to examine its therapeutic potential for pain treatment.