Non-woven experimental samples of wound dressings, made from natural degradable polymers, were produced and investigated. High-porous membranes were obtained by electrostatic formation of solutions of copolymers of 3-hydroxybutyrate-co-4-hydroxybutyrate [P(3HB-co-4HB)]. The set of pre-clinical assessments was performed, included testing of membranes in vitro and in vivo. Study was carried out by staining of blood cells with vital fluorochromic dyes, followed by analysis of activation of platelet adhesion, the ratio of the main morphological types of erythrocytes, measurements of changes of hemoglobin content in human blood, and hemolytic activity. The general toxic effect was investigated in experiment with white mice after the intraabdominal injection of water extracts of membranes. It was established, that direct contact with membranes had no negative influence towards cells of blood and showed no toxic effects in animal experiments