Two patient with acute intermittent porphyria with dominating neurological symptoms were described. Both patients were initially diagnosed and treated as Guillain-Barre syndrome. Diagnostic mistakes took place because of the lack of abdominal symptoms coexisting usually with the neurological and psychiatric features. Therefore the investigation of the urine level of PBG and ALA was not done. We also would like to point out that acute abdominal pain in a patient with porphyria may have other causes than porphyric attack.