Neurologic disorders represent the most severe complications of acute intermittent porphyria (AIP). Cognitive disturbances, bulbar and spinal weakness appear as the most critical neurological complications as they may lead to death or definitive motor weakness. A 38-year-old woman was admitted for an acute and painful tetra paresis occurring after a laparoscopy for an ovarian cyst. She also complained of abdominal pain treated with noramidopyrine, tachycardia, hypertension and hyponatremia. The electrophysiological examination showed a motor axonal neuropathy. The increase of Urine ALA at 268 micromol/l (N<38) and of at 235 micromol/l (N<5) strongly suggested AIP that was further confirmed by PBG desaminase deficiency in red cells. Thanks to the prescription of heme arginate (HA) at the dose of 3 mg/kg/day for 4 days, pain resolved immediately and motor function began to improve since the second day of treatment concurrently to a dramatic decrease of both urine ALA and PBG concentrations. Motor recovery was complete after 12 months of evolution. This case illustrates the potential severity of acute porphyric neuropathy when precipitating factors (noramidopyrine, surgery) are present in previously undiagnosed AIP. Moreover, motor neuronal function improved while HA therapy was initiated 22 days after the clinical onset of weakness. This tempts us to propose HA therapy at any stage of acute porphyric neuropathy.