Opuntia ficus indica cladodes are used in traditional medicine of many countries for their cicatrisant activity. The major components of cladodes are carbohydrate-containing polymers, which consist of a mixture of mucilage and pectin. In this paper we studied the cytoprotective effects of cladodes on experimental ethanol-induced ulcer in rat. The O. ficus indica cladodes administration gives rise to cytoprotection phenomena by breaking up the epithelial cells and stimulating an increase in mucus production. When O. ficus indica cladodes are administered as a preventive therapy, keep the gastric mucosa under normal condition by preventing mucus dissolution caused by ethanol and favouring mucus production. An increase of mucus production is also observed during the course of the curative treatment. The treatment with O. ficus indica cladodes provokes an increase in the number of secretory cells. Probably, the gastric fibroblasts are involved in the antiulcer activity.