The serotonin selective reuptakc inhibitors (SSRis) have clinically and ancedotally been associated with nausea and weight loss as a side effect of their action. The tricyclic antidepressants have been linked to carbohydrate (CHO) craving and weight gain in patients with major depressive disorders. This side effect has been attributed to the strong anti-histaminergic actions of these agents and is recognized as a causal factor of non-compliance in a substantial percentage of patients. CHO craving is an important feature and complication of the treatment of depression and is often ignored. A total of 18 patients were treated with the SSRI citalopram in our mood disorder clinic, In eight cases there was a significant increase in CHO craving together with weight gain shortly after initiation of treatment. The craving for CHO took on a phasic presentation. These cases are presented, together with data on the change in mood and anxiety symptom rating scales. Our observations appear paradoxical, given that serotonin (5-HT) typically mediates a reduction in CHO intake and that citalopram displays potent and select 5-HT-enehancing actions. However, the receptor binding profile of citalopram may predict a risk for inducing this adverse event. These, together with serotonergic, dopaminergic, histaminergic and other possible mechanisms are discussed. A profound influence on patient acceptability was observed, suggesting that the impact on compliance needs to be considered.