Modern research in the field of chondroitin sulfate chemical composition is considered. Clinical efficiency and safety are shown to depend on the nature and quality of the raw material used, ways of its technological processing and the degree of purification. The composition of chemical compounds (CC) variable is stated to represent the mixture of 2 main isomeric forms: chondroitin 4-sulfate and chondroitin 6-sulfate. In the animal tissue chondroitin 4-sulfate dominates, the content of which is 70 %; the content of chondroitin 6-sulfate is 30 %. The cartilages of sharks and other hydrobionts have got low content of chondroitin 4-sulfate (10 %) and chondroitin 6-sulfate 80 %. Complex polymeric structure and instability of CC composition make the problem of drug standardization on its basis complicated. The impurities encountered in substances are considered. The impurities are divided into several groups: related impurities, technological or mechanical ones uncharacteristic of CC. Comparative analysis of requirements for raw material from the point of view of normative documentation of different countries is carried out and their considerable difference is detected. It has been shown that for raising pharmacological activity the producer of drugs must take into account all the parameters of CC including the structural composition, molecular weight and presence of impurities.