The selective serotonin reuptake inhibitors (SSRIs) are rapidly emerging as preferred first-line drugs in the pharmacological management of post-traumatic stress disorder (PTSD). Citalopram, an SSRI with highly potent and selective serotonin reuptake inhibition, may be a useful agent for treating the intrusive, avoidance, and arousal symptoms that characterize PTSD. Fourteen adult subjects (12 with civilian-related post-traumatic stress disorder, and 2 with combat-related post-traumatic stress disorder) were entered into an 8 wk, open- label, fixed-dose trial of citalopram, commencing with 20 mg/d, and increasing to 40 mg/d after 2 wk. Eleven subjects completed 8 wk treatment and were included in the data analysis. Based on the Clinician-Administered Post-traumatic Stress Disorder Scale (CAPS-2), there was significant reduction in all core PTSD symptoms (re-experiencing, hyperarousal, and avoidance) by week 8. Nine of the 11 completers were classified as 'responders' on Clinical Global Impression Improvement scores. Secondary measures of depression (Montgomery-Asberg Depression Rating Scale) and anxiety (Hamilton Anxiety Scale) also improved significantly by week 8. Citalopram was tolerated well, and there were no dropouts due to adverse effects. Data from this preliminary open trial suggests that citalopram, an SSRI, may be effective for reducing the key symptoms of PTSD, however, these findings need confirmation in double-blind, placebo-controlled trials.