Celiac disease is an autoimmune disorder that affects the small intestine. It occurs when the body reacts negatively to gluten, a protein found in wheat, barley, and rye. This reaction damages the lining of the small intestine, leading to malabsorption of nutrients and various gastrointestinal symptoms. People with celiac disease may experience symptoms such as diarrhea, bloating, and fatigue. The only effective treatment is a strict, lifelong gluten-free diet, which helps heal the intestine and prevents further complications. Regular monitoring and support from healthcare professionals are essential for managing this condition effectively.