The aim of the study was to compare the pharmacokinetics of two formulations of 8-methoxypsoralen: a commercial tablet formulation (B) and capsules containing 8-MOP dissolved in a mixture of polyethylene glycol and glycerol (A). The pharmacokinetic parameters studied were the time and value of the maximum peak concentration of 8-MOP (TmaxandCmax) and the area under the curve (AUC) of concentration versus time. The main results were: an earlier peak plasma concentration for A (30 min versus 126 min); less variability in the absorption of 8-MOP and inCmaxfor A; a faster rate of elimination with A; and no significant difference between ratios of ingested dose and plasma levels reached. Thus, the more stable bioavailability of the new formulation was clearly demonstrated.