The clinical data of 102 patients referred to Leeds Dental Hospital from 1978 to 1987 with acute herpetic stomatitis confirmed by laboratory investigations were analysed. No gender difference was found. Differences in age distribution were marked. Only 5% of patients were aged less than 11 years, whereas the majority of cases (51%) occurred during the third decade. Statistical analysis confirmed a general trend for the mean age of patients to have increased progressively over the 10-year period.