In a general adult Swedish population recurrent herpes labialis (RHL) was found in 3.1% of 20,333 people aged 15 years and more. When a 2-year history of RHL was considered, the total prevalence was 17.4%. There was a slight predominance among women. Only slight differences were found between various age groups. In a fraction of the population studied, constituting 2771 people, interviews concerning cases of RHL were carried out. Thus, for example, most individuals referred to only one herpes episode a year; the most prevalent site of eruption was an area comprising both the vermilion border and the skin, and most of the lesions showed healing times of 5-8 days. The prevalence of RHL was influenced by some tobacco habits. Thus, the prevalence was significantly lower among smokers, and especially among pipe smokers, than among people with no tobacco habit at all. Snuff dipping did not seem to influence the prevalence values.