The possible influence of concomitant food intake on the bioavailability of the novel antidepressant zimeldine and its active metabolite norzimeldine was assessed in ten healthy female volunteers, who ingested a single dose of 200 mg zimeldine on an empty stomach and together with a standardized breakfast of 1 840 kJ. The plasma concentrations of zimeldine and norzimeldine were measured by a selective modern liquid chromatographic technique. Neither the peak concentration nor time to reach peak concentration nor elimination half-life nor the total area under the curve (AUC) of zimeldine was affected by concomitant food intake. For norzimeldine, the peak concentration showed a 10% reduction, but there was no change in any other parameter. Thus, the bioavailability of zimeldine and of its active metabolite norzimeldine is unaffected by food intake, suggesting that the drug need not be taken in a strictly defined relation to meals.