Porphyrias are a group of inherited or acquired disorders of certain enzymes in the heme biosynthetic pathway (also called porphyrin pathway). They are broadly classified as hepatic porphyrias or erythropoietic porphyrias, based on the site of the overproduction and mainly accumulation of the porphyrins (or their chemical precursors). They manifest with either skin problems or with neurological complications (or occasionally both).

The term derives from the Greek πορφύρα, porphura, meaning "purple pigment". The name is likely to have been a reference to the purple discolouration of some body fluids in patients during an attack. Lane, N. Born to the purple: the story of porphyria Scientific American blank">Fulltext. Although original descriptions are attributed to _Hippocrates, the disease was first explained biochemically by Felix Hoppe-Seyler in 1874, and acute porphyrias were described by the Dutch physician B.J. Stokvis in 1889.