A comparison was made between the effects of maprotiline, the sole action of which is to inhibit the reuptake of noradrenaline, of salbutamol and of viloxazine on hypothermia induced by reserpine, oxotremorine or apomorphine. The dose/effect curves in the three tests showed a similarity in profile between viloxazine and salbutamol, whereas no resemblance was evident between these two drugs and maprotiline. These facts suggest that viloxazine which has a weak effect on noradrenaline reuptake acts probably as antidepressant by betamimetic activity.