Background. There are a few data about the systemic influence of drugs, used in osteoarthritis. A hind limp arthropathy is characterized by progressive cartilage destruction and develops spontaneously in MRL/Mp-lpr/lpr (MRL/l) mice. These mice are a good model for assessment of drugs with chondro-reparitive activity. The aim of our investigation was to study healing effect of intramuscular injection (IMJ) of chondroitin sulphate (CS) on joint cartilage and tissue lesions. Material and methods. The age of all animals (60 mice - 30males and 30 females) at the experiment beginning was 5 months. Cartilage, heart, kidney and liver were studied in two groups as follows: the placebo group received 3 times per week 25 IMJ of 0,2 ml isotonic solution, CS group - received 3 times per week 25 IMJ of 0,2 ml 10% solution CS. After euthanasia tissues were fixed for 24 hours in 10% neutral buffered formaldehyde. Kidney, heart and liver were investigated by histological and histochemical methods. The material was studied by blind method. Results. At the end of the experiment only 5 males survived in placebo group, in the CS group - 15males and 10 females. The alive animals were decapitated. In placebo group fibrocartilage articular surface was destroyed and remodelled. Tide mark was absent. Acid glycosaminoglycanes (GAG) depletion and collagen network fragmentation have been estimated. Severe vasculitis in all organs were found. There were severe nephritis, myocarditis and hepatitis too. In the CS group cartilage was uniform, with normal thickness and layer differentiation. Cartilage reparation processes have been estimated as follows - the number of double-nuclear chondrocytes increased and accumulated in groups. GAG increased too. Collagen structure re-established. Tide mark was safe. Dystrophy and mild vasculitis in heart and liver, severe alteration in kidney were found. There was significant difference between the group results (p<0,05). Conclusion. Not only cartilage, but organic lesions, such as vasculitis, nephritis, myocarditis and hepatitis are influenced after chondromodulators’ treatment of MRL/l mice. These results provide some insight into the anti-inflammatory mechanism of CS action.