Alcohol is much more slowly eliminated in the fetus than in the mother (< 50%). The ethanol and its derivative the acetaldehyde have a constant dose-effect on the development of the nervous system central. The individual susceptibility to alchol teratogenic effect in utero is responsible of variable clinical phenotype. This teratogenicity is constant during all the development of the central nervous system. The diagnosis of fetal alcohol syndrome (FAS) associates three criteria: delay of pre- and postnatal growth, abnormal development of the central nervous system, craniofacial abnormalities. Cerebral malformations are extremely variable, being to relate to the various stages of development of the nervous system central. Neurochimic abnormalities interest mainly the mono-aminergic system. The backwardness is the best known consequence of SAF (34 to 851%). It is not constant. Facial dysmorphic results of joint abnormalities whose none is pathognomonic but whose grouping is evocative. Psychomotor instability is the most frequent expression on the behavioral phenotype.