Abscess-induced animals and normal animals were treated with /sup 67/Ga-citrate. Abscess, kidney, heart, lung, and spleen were excised and homogenized. After removal of the nuclear fraction, each of these homogenates was digested with protease. After digestion, the supernatants of the reaction mixtures were applied to a Sephadex G-100 column. Resultant eluates were analyzed for radioactivity, protein, uronic acids, and sialic acids. Sodium sulfate-/sup 35/S was administered to animals that were then treated by the same procedure as that followed for animals treated with /sup 67/Ga-citrate. In abscess, kidney, lung, heart, and spleen, sizeable amounts of /sup 67/Ga had been bound to the sulfated acid mucopolysaccharides with molecular weights of about 10,000, and to the sulfated acid mucopolysaccharides, a species whole molecular weights exceeded 40,000. Based on the results presented here, it is clear that /sup 67/Ga-binding substances in abscess and also in the above four organs are sulfated acid mucopolysaccharides.