Tests were carried out on the possibility of biodegradable copolymer d, l-lactide and E-caprolacton as a carrier system for a long-term substitution of progesterone and cortisole. During 120 days of the experiment almost linear profile of freeing of progesterone with average rate 0.5% of the initial amount of hormone (24 hours, what indicates a practical possibility of its application in hormonal substitution) was obtained. Simultaneously the influence of copolymer implants on the metabolism of collagen was tested marking the concentrations P I CP and P III NP in particular periods of the experiment. We did not notice any permanent changes of metabolism of collagen under the influence of the tested carrier system of the hormonal medicaments and the obtained changes of concentrations P I CP and P III NP are probably caused by the hormones freeing from the subgrade.