Com. polycarbonate was filled with halloysite, montmorillonite and a rhodamine B (0.3% by mass) and processed to plates used then for studying cytotoxicity by using 3-(4,5-dimethy1-2-thiazolyl)-2,5-dipheny1-2H-tetra-sodium bromide assay. The filled polycarbonate showed low cytotoxicity except for addn. of rhodamine B.