The aim of the present study is to evaluate the effects of sodium phosphate (NaP) and polyethylene glycol-electrolyte (PEG-EL) colon cleansing solutions on histopathology of 2,4.6-trinitrobenzene sulfonic acid (TNBS) and ethanol (E)-induced colitis in the rat and normal rat colon. The presence of hyperemia, inflammation and ulcer was evaluated to score of macroscopic morphologic damage. The microscopic criteria including ulceration, mucus cell depletion, crypt abscesses, inflammatory cysts, mucosal atrophy, edema, inflammatory cell infiltration, and vascular dilatation were evaluated to determine the extent of inflammatory reaction. Colitis findings were determined on the rats which were administered TNBS-E. Aphthoid lesions were seen 30% and 20 % of rats, respectively by NaP and PEG-EL solutions in healthy group. Microscopic examination of aphthoid lesions revealed edema within the lamina propria and lymphoid hyperplasia in the mucosa and submucosa without erosion, ulceration and inflammatory cell infiltration. No significant difference was statistically found either macroscopically or microscopically in terms of the effects of saline, NaP and PEG-EL solutions in healthy rats and rats with colitis (p > .05). Under the present conditions, we concluded administration of NaP and PEG-EL solutions did not cause evident morphological changes on the rectal mucosa macroscopically and microscopically, although in a proportion of rats aphthoid lesions seem as a marker of mucosal damage macroscopically.