Abstract： AIM　To compare two methods of quantitating spontaneou s pain-related re sponses on evaluating the analgesic effect of morphine. METHODS　After subcutaneo us injection of bee venom into the plantar of one hindpaw in rats, the nocicepti ve responses were evaluated by two different methods: by counting the number of flinching reflex and by the four grade weight scoring. RESULTS　 The suppressive e ffect of pretreatment with morphine i.v. was found. Pretreatment with 0.015, 0. 15, 0.3, 0.47, 1.5, 3.0 mg*kg-1 morpine i.v. significantly produced a dos e-dependent suppress ion of the bee venom-induced spontaneous pain-related responses (P<0.05). The inhibitory rates were 17, 39, 48, 52, 62 and 89 per cent. The ED50 of morphine was 0.29 mg*kg-1 . Pretreatment with 1.5 mg*kg-1 morphine i.v. produced significant sup pression on the bee venom-induced lifting/ licking nociceptive score. CONCLUSION　Pretreatment with morphin e i.v. can produce a dose-dependent suppression on the bee venom-induced spontaneous flinching ref le x. In the bee venom test, the spontaneous flinching reflex as quantitative measu re of spontaneous pain-related responses is more simple, stable and objective t han lifting/licking nociceptive score.