The healing processes of carinal reconstruction by suture materials; absorbable suture (Vicryl) and nonabsorbable suture (Prolene) were compared. 67 adult mongrel dogs underwent resection of two rings of the trachea and bilateral main bronchi. This was followed by end-to-end anastomosis of the reconstructed carina and the remaining trachea. 3-0 Vicryl or 3-0 Prolene were used respectively. At some intervals, each anastomosis was removed and was analyzed by bronchoscopy, microangiography, scanning electron microscopy (SEM) and light microscopy. Suture insufficiency occurred in two of 32 anastomosis sutured by Vicryl and four of 35 anastomosis sutured by Prolene sutures. Stenosis developed in one of the Vicryl group and two of the Prolene group. Vicryl showed more inflammation than Prolene for 3 weeks after surgery. In four weeks, the inflammation subsided. Anastomoses were of the same degree in both groups. In microangiography, vascular regeneration was abundant by 3 weeks, which normalized in 4 weeks showing a normal network in both groups. Normalization of the vascular network appeared the earliest at the membranous portion. Scanning electron microscopy showed no difference in the reconstruction of the cilia over the anastomosis area in the both groups. This term was 2 months. The order of reconstruction revealed by SEM was the same as observed by microangiography. But in the Prolene group, it took more than 3 months for the suture material to be completely covered with the epithelium. In light microscopy, inflammation was stronger in the group than by in the Prolene groups, and it continued for 4 weeks suture material could not be found in the anastomosis area with bronchoscopy.(ABSTRACT TRUNCATED AT 250 WORDS)