The microscopic finding of the mucosa was observed following oral administration of 10 mg/kg indomethacin in alcohol as solvent. The histological changes were observed from 6 hours after administration of indomethacin and the maxima1 injury was found at 24 hours. Structural changes of injury included hemorrhage, epithelial desquamation and inflammatory cell infiltration.

From the 3 day specimens, regeneration signs had started and in the 6 day specimens almost complete recovery of the mucosal epithelium was noted. The histochemical changes of the mucus were also observed from the 6 hr specimens. As far as neutral glycoprotein was concerned, the decrease was most significant in the 3 day o1d group, and besides, they showed minimal reaction to PAS stain.

For acidic mucus, the decrease was significant in the 24 hr group and the 3 day group showed minimal reaction to Alcian blue stain. It was noted that these changes of the mucus had recovered 6 days after the administration of indomethacin.