Numbers of women discharged from hospital after being treated for acute salpingitis decreased by 40% in Sweden between 1974 and 1984. Several factors argue that this decrease was real, rather than a shift from inpatient to outpatient treatment. (Outpatients here include those treated by general practitioners as well as at hospital outpatient clinics). The decrease was nation wide and included all age groups. Repeat episodes of the disease decreased more than first episodes. The main reason for the decrease seems to be more strict attitudes to sexual relationships, especially in young people. Public and professional awareness of genital chlamydial infections was probably a contributing factor.