The oedema induced in the paw of the Wistar rat by local injection of three different carrageenans allows us to determine the inflammatory activity of these sulphated polysaccharides. This activity is greatest for the lambda type, it is reduced for the iota compound and is smallest for the kappa carrageenan. 2. Reduction of plasmatic stores of kininogens by ellagic acid or inhibition of kinin formation by hexadimethrine reduce the inflammatory reaction induced by the three carrageenans. Inhibition of kininases by phenanthroline increases the oedema. Thus the kinin system is involved in the development of this type of oedema. 3. In Brown-Norway rats, which lack of plasmatic kallikrein and kininogens, the inflammatory activity of the three carrageenans is very small. By comparing the activity in Wistar rats and in Brown-Norway rats, it is concluded that the kinin system is the most important factor in the development of the inflammatory reaction induced by the three types of carrageenans.
