Question: what are the digestive system diseases?
Answer: Gastroesophageal Reflux Disease (GERD) ... 
Peptic Ulcer Disease (PUD) and Gastritis. ... 
Stomach Flu. ... 
Gluten Sensitivity and Celiac Disease. ... 
Inflammatory Bowel Disease (IBD) ... 
Irritable Bowel Syndrome (IBS) ... 
Constipation. ... 
Hemorrhoids.