Emotional lability or emotionalism is a relatively common phenomenon and frequently occurs following vascular or traumatic brain injury. It is distressing and embarrassing to sufferers and their families, and often interferes with rehabilitation. At present there is no satisfactory or reliable treatment for this condition. We describe an open trial using fluoxetine, a newer antidepressant with a specific serotonergic action, in the treatment of emotional lability due to brain injury. Six consecutive cases of emotional lability attending a rehabilitation unit were studied (five cases of cerebrovascular accident and one of traumatic brain injury). Response to treatment was measured using a modification of the scale described by Lawson and MacLeod [1]. All showed a marked improvement within one week of commencing fluoxetine and the drug was well tolerated with no reported side-effects. The speed of onset and degree of improvement suggest that fluoxetine may be a useful agent in the treatment of emotional lability due to brain injury. Our observations indicate that further investigation of the role of fluoxetine in the treatment of emotional lability is warranted.