Retinoids are vitamin A derivatives used in dermatology. One of them, isotretinoin, is frequently prescribed for refractory juvenile acne. The teratogenetic power of this drug is substantial, being estimated at 15 to 45% of exposures in utero. The risk is maximum in the first trimester of pregnancy and persists up to one month after treatment has been discontinued. The most frequently described multiple malformation syndrome involves the face, the central nervous system and the heart. There is also a 20 to 30% rate of spontaneous abortion. The authors report a case where exposure during the first trimester did not result in foetal malformation. From a full review of the literature the various malformations observed, the presumed mechanisms of teratogenesis and the strict rules of prescription and surveillance in women child-bearing age are presented. The problem of the measures to be taken in case of retinoid treatment during pregnancy is discussed. The teratogenic risk from other retinoids is dealt with.