General pharmacological action of 4-(o-Benzylphenoxy)-N-methylbutylamine hydrochloride (bifemelane hydrochloride, MCI-2016) was examined with regard to the effects mainly on the central nervous system. MCI-2016, at 30-100 mg/kg, p.o., only showed a weak sleep prolongation effect (mice), anti-convulsant action (mice) and a moderate facilitation of exploratory behavior, but produced no remarkable behavioral changes. Above the doses of 200 to 300 mg/kg, p.o., MCI-2016 produced a decrease in muscle or body tone, mydriasis and a slight decrease of locomotor activity. The drug, however, showed little influence on exploratory behavior, conditioned avoidance response and normal body temperature (rats). Normal body temperature in rabbits was also little affected by MCI-2016. Effects on EEG was characterized by moderate activation of spontaneous EEG and potentiation of arousal response by stimulation of the midbrain reticular formation (1.5-5 mg/kg, i.v.). The drug, however, did not significantly change the sleep-wakefulness cycle and REM-sleep in rats. MCI-2016 also showed little influence on spinal reflex potentials and neuromuscular junction at high doses (10 mg/kg, i.v.). These results may indicate that MCI-2016 has slight influence on overall behavioral and motor changes. Effects of MCI-2016 on acetic acid-induced writhing, carrageenin edema and corneal reflex were also examined. MCI-2016 showed moderate analgesic and anti-inflammatory actions at 50-100 mg/kg, p.o., and also showed local anesthetic action. The duration of local anesthetic action was relatively long but the drug produced no local damage.