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Also Known As

Acute peritonitis, Peritonitis colic


As in humans, peritonitis in a horse is a life-threatening condition that occurs when the protective membrane that lines the abdominal cavity and covers the intestines is punctured either by accident or because of a disease.

A sudden, acute episode of severe peritonitis following a rupture or injury to the stomach or the bowel releases toxic foreign material or bacteria into the peritoneal cavity and can be fatal within a few hours.

The peritonitis may be acute or chronic, and localized or generalized. A localized peritonitis affects a small area of the abdomen, usually with a chronic abscess that may be hard to pinpoint. It often manifests with the symptoms of colic and may be difficult to diagnose.

If the bowel has actually ruptured, little can be done to save the horse, and because of the shock and pain, most veterinarians will suggest putting the horse down as quickly as possible. Fortunately, less severe cases of peritonitis are treatable with a positive prognosis in many cases. .


  • Intense pain in the abdominal area
  • Raised heart rate
  • Raised temperature
  • Sweating
  • Evidence of shock
  • Loss of appetite
  • Dehydration
  • Weight loss
  • Diarrhea
  • Dullness of coat and eyes
  • Reluctance to move
  • Distension of abdomen
  • Lying down and rolling on the ground


Peritonitis can be the result of numerous causes and it can occur in horses of all ages, breeds, and genders.

Complications following abdominal surgery or castration, penetrating injury to the stomach or bowel, damage that occurs during breeding or foaling, uterine torsion, gastric or bowel rupture, a tumor, or an infestation of worms may cause contamination of the peritoneal cavity by bacteria or foreign matter leading to peritonitis.

The peritonitis may be confined to a small area of the abdomen with an abscess that causes colic-like symptoms, in which case it may take some time before a diagnosis is made because only vague symptoms, such as weight loss or dullness of coat and eyes, are exhibited.

In other cases, a sudden episode of severe, generalized peritonitis can have a devastating effect on the horse, causing acute pain, shock, and death within a short time.


Given the environment in which horses live, and the many causes of peritonitis, absolute prevention is impossible. Rapid diagnosis and aggressive therapy can successfully reduce both mortality and complication rates with many horses going on to make a full recovery.


Treatment of chronic peritonitis is directed at the underlying cause of the condition. Antibiotics to clear up infection and deworming agents such as ivermectin to get rid of parasites may be effective in some cases. A veterinarian can prescribe the best treatment given the age, activity level, and general physical condition of the horse.

In all cases of acute peritonitis, a knowledgeable veterinarian should be called immediately to determine the most effective treatment available. Horses with acute peritonitis require intensive intravenous fluid therapy, broad spectrum antibiotics, and correction of electrolyte imbalances.

Pain relief and control of endotoxic shock will be part of the treatment. Insertion of a nasogastric tube to decompress a distended stomach can lead to dramatic improvement. In some cases, the tube will need to be kept in place for a period of time.

Peritoneal lavage using quantities of salt solution to flush out the concentration of bacteria and/or foreign particles often helps relieve the condition. Surgical exploration for a continuing source of contamination or a difficult-to-diagnose cause may be necessary.

If the horse goes into advanced shock and sepsis or contamination is massive, the likelihood of returning the horse to a healthy condition may be so remote that the veterinarian will advise euthanasia.

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EquiMed staff writers team up to provide articles that require periodic updates based on evolving methods of equine healthcare. Compendia articles, core healthcare topics and more are written and updated as a group effort. Our review process includes an important veterinarian review, helping to assure the content is consistent with the latest understanding from a medical professional.