The short bowel syndrome is the result of a congenital or acquired loss of a large part of the small intestine. The most frequent causes of surgical resection of the intestine in infants are arterial or venous thrombosis, intestinal volvulus, necrotizing enterocolitis, and Crohn's disease. Symptoms include nutrient and electrolyte malabsorption, steatorrhea and diarrhea, which can result in failure to thrive. The consequences of extensive small bowel resections consist of nutritional deficiencies, gastric acid hypersecretion, nephrolithiasis, cholelithiasis and lactic acidosis. Of these, D-lactic acidosis is an infrequent but important complication because of the symptoms that it can produce. D-lactic acid in the human organism is generated by intestinal bacteria, D-lactate ingestion, or endogenous production in the methyl glycoxylase pathway. Neurological symptoms such as somnolence, ataxia or altered behavior in a patient with short bowel syndrome should make us think of D-lactic acidosis caused by bacterial overgrowth. We present the case of an 11-year-old boy with short bowel syndrome secondary to multiple resections during the postnatal period who was admitted to hospital for episodes of confusion and altered behavior. The diagnosis was lactic acidosis. Outcome was favorable due to prompt instauration of treatment.