C3 and constipation disorder: To investigate whether the laxative effects of Urd and AEtLP in C3-deficiency-induced constipation were accompanied by an improvement in the histopathological structure of the mid colon, the alterations in the mucosa layer, epithelial cells, lamina propria, and muscle layer were analyzed in the hematoxylin and eosin (H & E)-stained mid colons of C3 KO mice after Urd and AEtLP treatments.