A number of twenty dogs were used to evaluate clinically and histopatholo gically the coated polyglycolic acid (Dexon plus) in comparison to catgut as suture materials for the urinary bladder closure. The study revealed that the tissue drag and cutting which were serious drawbacks for the non coated polyglycolic acid did not occur when the coated material was used. The tissue reaction was mild towards coated polyglycolic acid in comparison to catgut which stimulated a chronic type of reaction. This may confirm that the coat improves the clinical charac ters of the suture material without inducing a pronounced tissue reaction.