We report a case of intoxication by metoclopramide, an antiemetic neuroleptic, in a breastfed child, causing an extrapyramidal syndrome. A 21-week-old breastfed child was brought to the pediatric neurology consultation following two episodes of unexplained dystonia. The anamnesis revealed that the mother had taken a rectal suppository of metoclopramide (10 mg) 48 hours before the first episode. The father was also treated by paracetamol codeine for capsulitis and the child had received paracetamol for teething. Blood toxicology analyses were performed at the first episode. A 3-cm strand of brown hair was collected during the consultation, one month after the second episode. The child had no further episodes of dystonia since the second event. The child’s blood toxicology analysis revealed the presence of metoclopramide at a concentration of 8 ng/mL. Hair analysis revealed metoclopramide at a relatively high concentration, with paracetamol, lidocaine, diazepam and nordazepam, and codeine. The presence of diazepam can be explained by medical care. The low concentration of codeine without its metabolite morphine, may suggest an external contamination by the environment, contact with people who had consumed this molecule, especially the child’s father. The interpretation of hair analysis in infants remains nevertheless delicate to discriminate consumption from environmental contamination. The presence of metoclopramide in the blood and hair is compatible with a passage of breast milk to the child. According to the literature, less than 5% of the maternal dose is found in the child. No case of intoxication through breast milk has been described, to our knowledge.