The effectiveness mechanism of the chlomipramine treatment was evaluated by sacral evoked response (SER) and dorsal nerve somatosensory cortical evoked potential (DN-SEP) testings in 15 patients with true premature ejaculation (TPE). We couldn't demonstrate any significant difference between the values of either latency times or amplitudes of the evoked responses determined just before and at the end of the treatment with chlomipramine in these patients. However, the sensory thresholds were 24.4 +/- 4.3 V in the pretreatment term and 30.2 +/- 7.3 V at the end of the treatment. This difference is statistically significant (P = 0.0031). Our results suggest that chlomipramine increases the sensory threshold for the stimuli in the genital area.