Gastroenteritis and diverticulitis are conditions that affect the digestive tract.

Gastroenteritis is an illness that’s usually caused by viruses, such as the rotavirus. Bacteria and parasites can also cause this illness. Viral gastroenteritis, or stomach flu, is contagious. Bacterial gastroenteritis, or food poisoning, is not.

Diverticulitis is a complication of diverticulosis, a noncontagious and common gastrointestinal condition.

Gastroenteritis and diverticulitis are not connected. One does not cause the other. Occasionally, a rare form of gastroenteritis, called eosinophilic gastroenteritis, may cause jejunal diverticulosis (diverticulosis of the small intestine). We’ll discuss diverticulosis and its connection to diverticulitis later on in this article.

Read on to learn more about the differences and similarities between gastroenteritis and diverticulitis.

Diverticulitis is caused by inflammation or infection of diverticula. Diverticula are small bulges, or sacs, that form in the walls of the large intestine (colon). Diverticula are less commonly found in the small intestine (jejunal diverticulosis).

The presence of diverticula indicates diverticulosis, a condition that becomes more common as people age. In the United States, more than 30% of adults between 50 and 59 years have diverticulosis. More than 70% of people 80 years and older have this condition.

Diverticulosis is typically asymptomatic and doesn’t require treatment. You can have this condition for a long time and not know it. If diverticulosis turns into diverticulitis, medical treatment is advised. Less than 5% of people with diverticulosis will get diverticulitis.

The triggers for diverticulitis are not completely understood. It’s thought that eating a low-fiber diet and being overweight are potential causes.

Diverticulitis typically causes pain on the lower left-hand side of the abdomen. This pain may radiate from one specific spot. Other symptoms may include:

  • fever
  • chills
  • cramps
  • nausea and vomiting
  • constipation

Gastroenteritis causes pain and inflammation in the stomach lining and intestines.

Viral gastroenteritis (stomach flu) is the most common form of this condition. Viruses that cause gastroenteritis include:

Bacterial gastroenteritis (food poisoning) is caused by food-borne or water-borne pathogens, such as salmonella. Parasites may also cause this condition.

Gastroenteritis can cause intense stomach pain. Other symptoms include:

  • nausea
  • vomiting
  • diarrhea
  • severe abdominal cramping

Gastroenteritis is usually self-limiting and clears up in a few days. Over-the-counter treatments, such as anti-diarrheal medication and drinking lots of fluids, are often enough to reduce severe symptoms.

This condition doesn’t usually require medical treatment in healthy adults. However, you should seek medical attention for worsening symptoms or for symptoms that don’t let up after several days.

Dehydration is a potential complication of gastroenteritis. Babies, children, and older adults should seek medical treatment for this condition, to avoid fluid and electrolyte loss.

Diverticulitis and gastroenteritis often present with similar symptoms. Any symptom that worries you should be brought to the attention of your healthcare professional.

The pain associated with gastroenteritis may be more diffuse than the pain caused by diverticulitis.

Diverticulitis often causes sharp pain to occur in the lower left side of the abdomen. This type of pain always warrants medical attention, especially if you have ovaries. Pain caused by ovarian cysts and other conditions of the female reproductive tract can mimic diverticulitis.

If you have gastroenteritis, it’s important to avoid dehydration. Symptoms of dehydration include:

  • dark urine
  • headache
  • fatigue
  • dry mouth
  • sunken eyes
  • lightheadedness
  • intense thirst
  • dizziness
  • constipation
  • reduced urine output
  • reduced tear production (a warning sign in infants and children)
  • dry skin
  • rapid heartbeat

Severe dehydration is a medical emergency. Any signs of this condition should be assessed by a healthcare professional.

Diverticulitis requires medical treatment to clear up the infection and eliminate the potential for complications. These may include an abscess (pus-filled sac) or peritonitis. To treat diverticulitis, your doctor may recommend antibiotics and a liquid diet for several days.

Diverticulitis and gastroenteritis are two unrelated conditions that affect the gastrointestinal tract. Since their symptoms are similar, they may be mistaken for each other. Symptoms of both conditions, such as stomach pain, should be discussed with a healthcare professional.