This chapter provides a comprehensive overview of gastrointestinal (GI) tract pathology, exploring inflammatory, infectious, neoplastic, and congenital conditions. Inflammatory diseases such as Crohn’s disease, ulcerative colitis, and diverticulitis are discussed, along with complications such as peritonitis and ischemic enteritis. Infectious agents, including Cryptosporidium parvum and Giardia duodenalis, are highlighted for their role in enteric disorders. Congenital abnormalities such as atresias and acquired conditions like volvulus are examined for their clinical implications. Neoplastic pathologies include adenocarcinoma of the stomach, carcinoid tumors, gastrointestinal stromal tumors (GIST), and syndromic associations such as hereditary nonpolyposis colon carcinoma (HNPCC) syndrome. Distinctive features of malignancies, such as signet ring cells and linitis plastica, are elaborated alongside precancerous lesions such as tubular adenoma. The chapter also explores vascular complications, including esophageal varices, and their consequences. Radiological and histological hallmarks, such as punched-out ulcerations, provide valuable diagnostic insights. This detailed exploration integrates pathology, clinical findings, and diagnostic techniques, offering a robust understanding of GI tract diseases.