SummaryThe authors relate their experience of 36 cases of porphyria : 14 cases of acute intermittent porphyria, 4 cases of mixed porphyria and 18 cases of pure cutaneous porphyria. They review the main clinical, biochemical and biological characteristics of these groups of patients. The factors inducing porphyria and the evolution of the disease are also discussed. Two unusual forms of porphyria are presented in the group of pure cutaneous porphyria : a melanodermic form and a sclerodermic form with mutilations. Reflections on the biochemical diagnosis of the different forms of porphyrias, on the main causes of error in the detection of porphobilinogen by the Watson-Schwartz reaction and a survey of the different possibilities of therapy end this review of clinical cases.