Crohn's disease is an inflammatory bowel disease (IBD). It causes inflammation of the digestive tract, which can lead to abdominal pain, severe diarrhea, fatigue, weight loss and malnutrition. Inflammation caused by Crohn's disease can involve different areas of the digestive tract in different people. With Crohn’s disease, the body’s immune system attacks and damages bowel or gastrointestinal systems. Crohn’s is a chronic condition with no known cure.