The widespread use of repeatedly heated cooking oils, especially in developing regions, poses significant health risks, including oxidative stress-induced intestinal damage. This study investigates the histological and protective effects of vitamin C against the harmful impact of thermally oxidized oils on intestinal health. Two oil types, clean oil, and repeatedly heated cooking oil (RHC), were tested with and without vitamin C supplementation. Rats were divided into four groups receiving diets containing clean oil, RHC oil, or combinations with vitamin C. Histological analysis of hematoxylin and eosin-stained intestinal tissues was performed. The clean oil group exhibited normal villous and crypt architecture with minimal vacuolar degeneration. In contrast, the RHC oil group displayed severe necrotic changes, epithelial disruption, and glandular degeneration. Cellular damage, including epithelial necrosis and pyknotic nuclei, was prominent. Vitamin C supplementation provided partial protection, preserving villous structure, and reducing cellular damage, yet vacuolar degeneration and goblet cell hyperplasia persisted. These adaptive changes suggest tissue responses to oxidative stress but may also indicate early precancerous alterations. Findings confirm that repeated oil heating severely compromises intestinal health by inducing epithelial necrosis, glandular degeneration, and metaplasia. While vitamin C preserved some tissue architecture, its protective effects were insufficient to counteract oxidative damage fully. Public health interventions should aim to reduce reliance on reused cooking oils and promote antioxidant-rich diets to mitigate oxidative stress-related damage.