A 24 year-old patient with a short-bowel syndrome receiving home parenteral nutrition in addition to oral feeding for 32 months was treated by oral trimethoprim-sulfamethoxazole for urinary tract infection. Three days later, he developed neurologic disorders associated with severe hyperchloremic acidosis and high plasma level of D-lactate. This is a rare complication of intestinal malabsorption due to small bowel by-pass or extensive resection due to transient alteration of intestinal microflora induced by the oral antibiotic treatment. Diagnosis requires a high indice of suspicion.