The aim of the work was to investigate the preventive effect of Chondroitin Sulfate on the concentration of C-reactive protein and medium weight molecules in blood serum of rats at local inflammation of the hind limb. The studies were conducted on white non-linear, sexually mature male rats weighing 180–240 g, in compliance with the general ethical principles of experiments on animals. All animals were divided into four experimental groups. The first group – control: animals sub-planar injected 0.1 ml of 0.9 % NaCl solution into the posterior right limb. The second group – animals received a therapeutic dose of 3 mg x kg-1 chondroitin sulfate daily for 28 days daily. The third group – animals were infused intramuscularly with 0.1 ml of 0.9 % NaCl solution in the posterior right limb for 28 days and for 29 days inflammatory edema of the limb was stimulated (animals were sub-planar injected with 0.1 ml of 1 % carrageenan solution to the posterior right limb ) The fourth group – for 28 days rats were daily intramuscularly injected with a therapeutic dose of 3 mg x kg-1 chondroitin sulfate, after which on 29th day, inflammatory edema of the limb was stimulated. Animals were killed 3 hours after injection of carrageenan solution according to the protocol of the ethical committee, and then blood sampling for further research was quickly taken. The total number of animals involved in experimental studies was 40 individuals. Creactive protein concentration was determined by turbidimetric method. The content of medium weight molecules was determined by screening method. It has been established that with carrageenan-induced inflammation of the posterior limb, the concentration of C-reactive protein and medium weight molecules increases in the serum. It was shown that the prophylactic administration of chondroitin sulfate based drug on animals with carrageenan-induced inflammation restored the abovementioned parameters.