The antinociceptive effect of sarpogrelate, a new selective 5-hydroxytriptamine (5-HT) 2A receptor antagonist, in the formalin test was examined in rats. Sarpogrelate was administered intraperitoneally, locally (subcutaneously at the formalin test site) or intrathecally 10 min before formalin injection. Intraperitoneal (1–100 mg/kg) and local (0.01–1 mg) administration of sarpogrelate suppressed flinching behavior in both phases 1 (0–9 min) and 2 (10–60 min) in a dose-dependent manner. Intraperitoneal (100 mg/kg) and local (1 mg) injection 7 min after formalin injection reduced phase 2 flinches to the same degree as with the pre-treatment. Intrathecal administration (1–100 μg) showed no antinociceptive action, and facilitated phase 2 flinches at 10 μg. The plasma concentration of sarpogrelate after local administration of 1 mg was lower than after intraperitoneal administration of 10 mg/kg, although local administration produced more potent antinociception. The data imply that the antinociceptive effect of sarpogrelate results mainly from an action at peripheral sites.