Emotional lability may be a part of the syndrome of pseudobulbar palsy. Here we report our experience with fluvoxamine, a selective serotonin reuptake inhibitor, used to treat 10 patients with emotional incontinence. Over a 7-month period, we studied and treated 10 consecutive patients (mean age, 61 +/- 8 years) attending our department: four had amyotrophic lateral sclerosis (progressive bulbar palsy form), four had clinically definite multiple sclerosis, and two had had strokes. They were given a single evening dose (100 mg) of fluvoxamine. All 10 patients had > 30 affective outbursts daily. It was observed that in 2 to 6 days, all the patients improved, the number of emotional outbursts dropping to none to five per day. This result suggests that the serotoninergic system may be implicated in emotional lability. The short latency of improvement we observed in our patients suggests that the mechanism of fluvoxamine for treating emotional lability differs from its mechanism for treating affective disorders.