Sensory or P50 gating, as measured with the double click paradigm, reflects a slow inhibitory preattentional information process. It protects living organisms from being flooded by environmental stimuli. The effects of a single dose of diazepam (10 mg) on the amplitude of the P50's and P50 gating, as measured from auditory evoked potentials elicited by double clicks (80 dB white noise, interstimulus interval 500 ms) were investigated in a double blind, placebo controlled study in healthy volunteers. P50 gating was found, however diazepam had no effects on the amplitude of the P50, nor on P50 gating. The results contribute to the specificity of psychoactive drugs to control gating and demonstrate that this slow inhibitory process is not effected by this benzodiazepine. Moreover, the results confirm that P50 and P50 gating are indeed preattentive processes that are not controlled by diazepam.