Abdominal sounds (bowel sounds) are made by the movement of the intestines as they push food through. Since the intestines are hollow, bowel sounds can echo throughout the abdomen much like the sounds heard from water-pipes. The great majority of the bowel sounds are benign and simply indicate that the gastrointestinal tract is working. Abdominal sounds are evaluated by listening to the abdomen with a stethoscope (auscultation).

While majority of bowel sounds are normal, there are some instances where abnormal bowel sounds provide valuable information about the health of the body.

Absent bowel sounds, called ileus, is a condition in which the examiner is unable to hear any bowel sounds after listening to the abdomen. This indicates a lack of intestinal activity. Many medical conditions may lead to this but it is important to evaluate it further because gas, secretions, and intestinal contents can accumulate and rupture the bowel wall.

Reduced (hypoactive) bowel sounds include a reduction in the loudness, tone, or regularity of the bowel sounds. They indicate a slowing of intestinal activity. Hypoactive bowel sounds are normal during sleep, and also occur normally for a short time after the use of certain medications and after abdominal surgery. Very often decreased or absent bowel sounds may indicate constipation.

Increased (hyperactive) bowel sounds are sometimes heard even without a stethoscope. Hyperactive bowel sounds reflect an increase in intestinal activity. This can sometimes be seen in diarrhea and after eating.

Abdominal sounds are always evaluated in conjunction with symptoms such as nausea, vomiting, presence or absence of bowel movements or gas. If bowel sounds are hypo or hyperactive, along with abnormal symptoms, continued evaluation by a health care provider is important. For example, absent bowel sounds after a period of hyperactive bowel sounds are significant findings which can indicate that rupture of the intestines, or strangulation of the bowel with subsequent death (necrosis) of the bowel tissue may have occurred.

Most of the sounds that you hear your stomach and intestines make are due to normal digestion and are no need for concern. However, if other troubling symptoms occur, a doctor can use a stethoscope to listen to abdominal sounds and determine if there is a problem. Many conditions may cause hyper or hypoactive bowel sounds. Most are benign in nature and require no treatment. However, the following are a list of more serious conditions that can present with abnormal bowel sounds.

Hyperactive, hypoactive, or absent bowel sounds:

• mechanical bowel obstruction (caused by hernia, tumor, adhesions, or similar conditions that can physically block the intestines)
• blood vessel obstruction and its resulting tissue damage (for example, blood clots can cause mesenteric artery occlusion, which prevents the intestines from obtaining a proper blood flow)
• paralytic ileus, a problem with the nerves to the intestines (reduced nerve activity can result from infection, overdistended bowel, trauma, bowel obstruction, vascular obstruction, and chemical imbalances such as hypokalemia).

• drugs that reduce intestinal movements, including opiates (such as codeine), anticholinergics, phenothiazines, and others
• general anesthesia and spinal anesthesia
• irradiation of the abdomen (radiation therapy for cancer)
• surgery in the abdomen (may cause reduced bowel sounds for 1 to 5 days)

• diarrhea (any cause including emotional stress)
• Crohn's disease
• GI bleeding
• ulcerative colitis
• food allergy
• infectious enteritis