The gastrointestinal tract of the digestive system is susceptible to various disorders.

The incompetence of the lower esophageal sphincter results in the backflow of stomach acid into the esophagus, causing irritation and inflammation of the lining.

This results in gastroesophageal reflux disease, causing heartburn, chest pain, and swallowing difficulties.

In the stomach, infection by bacteria like Helicobacter pylori, prolonged use of nonsteroidal anti-inflammatory drugs like ibuprofen, chronic alcohol consumption, or immunological reactions can adversely affect the gastric mucosa.

These changes may cause inflammation of the stomach lining, resulting in gastritis.

They can also erode the stomach or upper duodenal lining, forming peptic ulcers.

Celiac disease is an autoimmune disease. Consumption of gluten, found in wheat, barley, and rye, can trigger symptoms in individuals already diagnosed with this disease or with gluten intolerance. This leads to intestinal damage and symptoms like diarrhea, weight loss, and fatigue.

Lastly, irritable bowel syndrome is a complex gastrointestinal disorder caused by unexplained changes in gastrointestinal motility and stress, accompanied by bloating, nausea, irregular bowel habits, and mood changes.