A woman aged 35 years had a classical picture of acute intermittent porphyria. However, the diagnosis was only made after repeated clinical investigations by internists, gastroenterologists, gynaecologists and surgeons working at a university hospital, and after an unnecessary laparotomy. Recent data indicate that acute intermittent porphyria is not a very rare disease. It may run a serious invalidating and life-threatening course. Its manifestations vary and may lead to very different clinical pictures.