Laser stimuli (LS) were used to induce sudomotor skin responses (SSRs) in ten healthy human subjects. LS were applied to the dorsum of the hand by means of a CO 2 laser stimulator at an intensity of 120% pain perception threshold. SSRs induced by LS were of longer latency than those induced by electrical stimuli. However, response amplitude and duration were similar with either stimuli. The possibility to activate the sudomotor system by means of stimulation of pain afferents might be of clinical applicability for the functional assessment of pain pathways.