The distribution of radioactivity in rats after intravenous or oral administration of 14C-labelled N-N'-dicyclopropyl-methyl-piperazine-dichlorhydrate (14C-Ino 2628-CZ) demonstrated that the labelled compound was widely distributed in the body. An important diffusion of the isotope was found in the central nervous system, the gastric mucosa and several glands. Only small amounts of radioactivity were found in these organs 24 h after dosage.