Because of the potential hepatotoxicity of retinoids, prescription of isotretinoin is always very carefully made in healthy subjects, and prohibited in case of concomitant hepatopathy. Gilbert's syndrome consists of chronic, mild, unconjugated hyperbilirubinemia. In this syndrome, isotretinoin has been reported twice to be perfectly tolerated, and once even beneficial. We report here a new case of good tolerance and even improvement of a Gilbert's syndrome during isotretinoin therapy.A 17-year-old man with Gilbert's syndrome presented with a nodulocystic acne. Topical agents had been inefficient, and cyclines bad tolerated. Thus isotretinoin has been gradually introduced, with a regular monitoring of the liver function. We observed a steady decrease of the bilirubinemia during the course of isotretinoin, and then a reappearance of hyperbilirubinemia as soon as posology was diminished and particularly after completion of isotretinoin therapy.A review of the literature finds only very few cases of hepatic injuries caused by isotretinoin, contrary to etretinate. Safety of isotretinoin in Gilbert's syndrome was first observed in 1984, but its beneficial effects have only recently been described by Wang et al., and we report here a similar case. Pharmacological mechanisms remain hypothetic. However, considering the prevalence of Gilbert's syndrome and its usual first expression during postpubertal period, it seems to us interesting for therapeutic practice to know that isotretinoin is not less safe in these patients.