Gastrointestinal diseases and disorders refer to conditions that affect the digestive system, including the esophagus, stomach, intestines, pancreas, liver, and gallbladder. These conditions can range from mild to severe and may cause symptoms such as abdominal pain, bloating, diarrhea, constipation, nausea, and vomiting. Common gastrointestinal diseases and disorders include gastroesophageal reflux disease (GERD), irritable bowel syndrome (IBS), inflammatory bowel disease (IBD), and celiac disease.