Stomach cancer, also known as gastric cancer, arises in the lining of the stomach. Risk factors include infection with Helicobacter pylori bacteria, a diet high in salty or smoked foods, smoking, obesity, and family history. Symptoms may include abdominal pain, nausea, vomiting, unintended weight loss, indigestion, and blood in the stool. Diagnosis involves endoscopy, biopsy, and imaging tests. Treatment options depend on the cancer's stage, size, and location, and may include surgery, chemotherapy, radiation therapy, or targeted therapy. Prevention strategies include a healthy diet, avoiding smoking, treating H. pylori infection, and regular screening for high-risk individuals. Early detection improves treatment outcomes.