The incidence and significance of gray patches on the hepatic surface found at laparoscopy was investigated in 50 patients with chronic hepatic porphyria. The color change was found in 38 patients; in 28 patients well defined gray dots were found. The incidence is not related to the degree of the metabolic disturbance. The gray patches contained 3-9 times more porphyrine than adjacent normally colored areas. Gray color and histological changes do coincide.