Ileus: What Is It?

Medically Reviewed by Poonam Sachdev on December 04, 2023
6 min read

Ileus is a temporary condition where your intestine can’t push food and waste out of your body. Your intestine is a long and winding tube inside of your body that attaches your stomach to your anus. It has two parts, small and large. The small intestine's main job is to break down the food you eat. The large intestine, or colon, absorbs water and uses strong, wavelike movements to push broken-down food and waste to your anus so you can poop.

When your intestine stops making those wavelike movements for a while, ileus occurs. It usually lasts 1-3 days.

Ileus vs. obstruction

Ileus isn't the same thing as an obstruction or blockage in your intestines. With ileus, the intestinal walls can't push the contents of your digestive tract forward, and this is known as a nonmechanical bowel obstruction. If something physical prevents the contents from moving, you have a mechanical bowel obstruction. There could be several reasons for a physical blockage, and it can happen anywhere in your colon, right down to the rectum. Some causes include:

  • A foreign object that was swallowed
  • Impacted (hardened) stool
  • Tumors
  • Twisted intestines, called volvulus
  • Intussusception, which happens when one part of the intestine “telescopes,” or slides, into another part. Intussusception is the most common cause of intestinal obstruction in young children aged 3 and younger.
  • Scar tissue
  • Hernia
  • Gallstones (rare)


There are several types of ileus depending on the cause. They include:

Postoperative ileus

This type of ileus is the most common. If you’ve had surgery, particularly abdominal surgery, you may have wondered why medical staff were so concerned about you having your first bowel movement. Doctors don’t understand the exact cause, but the intestine can be slow to go back to full function after general anesthesia and surgery, sometimes taking up to 72 hours.

Paralytic ileus

A paralytic ileus happens when the intestinal wall becomes paralyzed and unable to push contents forward. The disruption arises when something triggers the muscles or the nerve signals to stop working as they should. It can happen in just one section of the intestine or along the whole digestive tract.

Possible causes include surgery or infection, certain medications, an imbalance of electrolytes (salt, water, etc.), or changes in your metabolism.

Meconium ileus

A meconium ileus only affects newborns. Meconium is the first stool or bowel movement after birth, although some babies may release meconium while still in the womb or during the birth process. Meconium is thicker than regular stool, and it can block the intestine. While meconium can cause a physical bowel obstruction, it's still called meconium ileus. 

It isn't always the case, but an infant who has meconium ileus has a high chance of having cystic fibrosis.

Gallstone ileus

A gallstone ileus, as with meconium ileus, is an actual physical obstruction. It's very rare and happens when a gallstone travels from the gallbladder into the intestine.

Ileus has many potential causes, including:

  • Surgery, especially when doctors have to shift your intestines
  • Medicines that affect your intestine, including:
    • Anticholinergics, such as atropine and scopolamine
    • Opioids, such as morphine and oxycodone
    • Tricyclic antidepressants, such as amitriptyline and nortriptyline (Pamelor)
    • Phenothiazines, such as thioridazine HCL and prochlorperazine (Compazine)
  • Infections in your midsection, such as appendicitis (inflammation of the appendix) or diverticulitis (inflammation or infection of small pouches, called diverticula, on the walls of the intestines)
  • Health issues such as kidney failure, heart attack, and hypothyroidism (when your thyroid gland doesn’t make enough of certain important hormones)
  • Mineral levels that are too low or high, such as potassium or calcium
  • Injury to arteries that send blood to the belly
  • Cystic fibrosis (a disorder of your genes that causes severe damage to the lungs and other organs)
  • Certain progressive diseases, such as Parkinson’s disease or Crohn’s disease, although it's rare in this case

You’ll feel symptoms in your stomach area for 24-72 hours. You may:

  • Feel bloated from a buildup of gas and liquid in your belly
  • Feel sick to your stomach (nausea)
  • Throw up (vomit)
  • Find it hard to poop (constipation)
  • Not want to eat
  • Have stomach cramps
  • Have watery stools
  • Be dehydrated

Ileus can happen to anyone, but some people are at a higher risk. Risk factors include:

  • Older age
  • Obesity
  • Poor general health

Certain medical conditions may also make you more likely to have ileus, such as:

  • Reduced blood flow to the intestines
  • Major weight loss
  • Serious infection
  • Serious electrolyte imbalances
  • Digestive disorders, such as irritable bowel syndrome or diverticulitis
  • Diabetes
  • Surgery, especially abdominal surgery
  • Sepsis, which can result from any type of infection, such as pneumonia or surgical infections
  • Radiation therapy near the abdomen, as for cancer treatment

To diagnose ileus, your doctor will take your medical history, including your most recent symptoms. This will be followed by a physical exam.

Your doctor will use a stethoscope to listen to the sounds your belly makes. Normal sounds like clicks and gurgles mean everything's probably OK. No sound could be a sign of ileus. If there is concern that you could have ileus, you may be sent for some of these tests:

  • Blood tests to measure your electrolyte and mineral levels and to rule out other conditions that could cause your symptoms
  • Imaging tests, such as abdominal X-rays and abdominal CT scans, to get pictures of the bowels
  • Upper gastrointestinal (GI) and small bowel series:
    • Barium enema: Barium is inserted into your lower intestines by enema, and an X-ray follows its path to check for abnormalities.
    • Upper GI series: You drink a “milkshake” that contains barium. A special X-ray follows the path of the drink as it goes through your small/upper intestine.

Sometimes, you don’t need treatment for ileus, because it will go away on its own. If you do need treatment, it will depend on how bad your symptoms are and the cause. Your doctor might suggest:

  • No food or fluids by mouth for 24-72 hours. Resting your intestine may help it regain its ability to move the contents through.
  • Change in your medications. Your doctor may stop or cut back on strong pain relievers (opioid analgesics) or other medications that may be causing your symptoms.
  • Prokinetics. Prokinetics are medications that could “reboot” your intestine, allowing it to push the contents forward again.
  • IV fluids. Given to help correct electrolyte imbalances, these also provide fluid and nutrients if you're dehydrated.
  • Nasogastric decompression, or suction to relieve a buildup of gasand liquid. Your doctor passes a tube, called a nasogastric tube, through your nose and into your stomach or small intestine. Then they'll use suction to drain fluid and air, and relax pressure and bloating. If the problem is in your large intestine, the tube is passed through your anus.
  • Electrical stimulation: It's used to encourage movement in the intestine.
  • Sitting in an upright position, especially for patients who may have spent a lot of time lying down.
  • Surgery: It isn’t usually required, but in some cases, it may be if the ileus doesn’t go away. Types of intestinal surgery include:
  • Stents. A stent is a tube that bypasses the affected area in the intestine.
  • Resection. This surgery involves removing the affected part of the intestine and reattaching the remaining ends.
  • Ostomy. An ostomy is an opening in your abdominal wall. A surgeon makes a cut in the intestine and redirects it through the new opening (ostomy), so you can empty the contents into an ostomy bag.

Your doctor will keep an eye on you in the hospital until you're well enough to go home. This should be within a few days. Your doctor will likely want to see you for a follow-up appointment.

It's rare, but there could be some complications, such as:

  • Perforation, or a hole, in the intestinal wall
  • Tissue death (necrosis)
  • Infection of the abdominal cavity (peritonitis)

Signs that there may be a problem include:

  • A fever of 100.4 F (38 C) or higher
  • A swollen belly or pain that doesn’t go away
  • Trouble pooping or passing gas
  • A queasy feeling or throwing up
  • A full feeling in your stomach after small amounts of food or drink
  • Bleeding from your rectum (last section of the large intestine)
  • Poop that's black or looks like tar

Contact your doctor immediately if you experience any of these symptoms. If you can’t get in touch with your doctor, go to a hospital and tell them that you recently were diagnosed and treated for ileus.