The shedding of herpes simplex virus type-1 (HSV-1) into the saliva was compared in 28 patients with oral cancer and 26 patients with genital or urological cancer. All subjects tested positive for HSV-1 specific antibody. A statistically significant (p less than 0.001) difference was found: infectious viruses were isolated from 12 (39.8%) of the oral cancer patients versus only 2 (7.6%) of the genital or urological patients. This indicates that direct stimulation of peripheral nerves during surgery was responsible for the greater reactivation of HSV-1.