Gastroenteritis is an inflammation of the lining of the stomach and intestinal tract. It can be caused by food poisoning, food allergies, or infections. The pain is crampy, diffuse, and may come on suddenly. There is nausea, vomiting, and diarrhea. If the cause is infectious, there may be a fever.
Constipation is difficulty in emptying the bowels.
The pain is often sudden and may be either constant or crampy. Although the pain is usually diffuse, it can be localized to the left side of the abdomen. Constipation does not cause a fever. Irritable colon, which is also known as spastic colon or mucous colitis, is a disturbance of large intestine function. The condition is made worse by periods of emotional stress.