The Clinical Effectiveness Group of the Medical Society for the Study of Venereal Diseases and the Association of Genitourinary Medicine published guidelines on the management of pelvic inflammatory disease in 1999. Subsequently, the use of ofloxacin has increased in our department. However, ofloxacin can cause serious psychiatric side effects, particularly in those with a past psychiatric history. This is of relevance to genitourinary medicine (GUM) physicians as there is a high prevalence of psychiatric illness amongst patients attending GUM clinics. We present two cases of ofloxacin causing severe psychiatric symptomatology, in one case causing an acute psychotic reaction. It is recommended a psychiatric history is taken prior to prescribing ofloxacin and that consideration is given to alternative therapy for those with previous psychiatric illness.