The document presents a detailed overview of preclinical screening methods for antiulcer drugs, focusing on the pathophysiology of peptic ulcers and various screening techniques. It describes in vivo methods such as pylorus ligation in rats and stress-induced ulcers, as well as in vitro assays for evaluating the effectiveness of potential treatments. The document concludes with an emphasis on the importance of these models in understanding ulcer formation and evaluating therapeutic interventions.