The two can happen at the same time—but it doesn't necessarily mean one caused the other.

The symptoms of constipation are pretty standard: having fewer than three bowel symptoms a week; stool that's hard, lumpy, or difficult to pass; feeling like you haven't passed all of your stool when you do go. All of these symptoms—though not entirely normal—are common. But what if your constipation is paired with something a little more worrisome, like a fever? Can constipation cause a fever, or is it a sign that something a bit more serious is going on?

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Credit: Getty Images / AdobeStock

First, the good news: There's a clear, simple answer to that question—and it's that, no, constipation can't directly cause a fever, Rudolph Bedford, MD, gastroenterologist at Providence Saint John's Health Center in Santa Monica, CA tells Health.

Fever is a response to an illness or infection, according to the US National Library of Medicine (MedlinePlus). Your body is trying to kill off the bacteria or virus by creating a higher-than-normal temperature that makes it difficult for pathogens to survive. That higher body temperature also activates your immune system to get to work.

Constipation, on the other hand, is caused by your stool moving through your colon more slowly than usual, per the National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK). This slower movement could be caused by dehydration, a change in your diet, a lack of exercise, or certain medications, the American College of Gastroenterology says. That's of course just one reason you could be constipated: the NIDDK says delayed emptying of the colon or other functional gastrointestinal disorders (like irritable bowel syndrome) could be at the root of your bathroom issues too.

In the grand scheme of things, constipation and fever aren't directly related—so if a fever is present with constipation, it means there's an underlying cause for both. "Fever is a sign of some inflammatory process that's going on," says Dr. Bedford. And that means you should start working towards figuring out what's going on.

First things first: You'll want to verify that you do indeed have an actual fever, and you'll need a thermometer to that. "A lot of people feel feverish, hot chills, fatigued, when you feel sick, but it doesn't mean you're actually running at a higher temperature," Elana Maser, MD, assistant professor of gastroenterology at the Icahn School of Medicine at Mount Sinai and gastroenterologist at the Feinstein IBD Center at Mount Sinai Hospital in New York City tells Health. But if a thermometer reveals your temperature has spiked to somewhere around 100–101 degrees Fahrenheit, that's a true fever, and it's time to seek medical care imminently. (Though, keep in mind, even if things just feel off, it's never a bad idea to check in with your doctor.)

Once you've verified that you have both constipation and a fever, it's time to check in with your doctor—you don't want to try to figure things out on your own. "If you have fever and constipation, you shouldn't be self-diagnosing," says Dr. Maser. Those two symptoms together aren't specific enough to help you narrow diagnosis down, and whatever it is, you'll likely need medical treatment.

One likely culprit? Diverticulitis, according to Dr. Bedford. Diverticula are small, bulging pouches that can form along the colon, according to MedlinePlus. Many people have them—this is a condition called diverticulosis—and they don't cause problems. But in some instances, bacteria can get trapped in these pouches and lead to infection and inflammation, which is then called diverticulitis. In addition to fever, diverticulitis can also cause pain on the left side of your abdomen, which can be severe and sudden or mild and increase over time. Some people experience nausea and vomiting, too, per the NIDDK. Diverticulitis requires antibiotics to treat, says Dr. Bedford, so it's not something you want to wait out. 

Whether it's diverticulitis or not, once you get to a hospital, you'll likely have a thorough workup and possibly even a computerized tomography (CT) scan in order to determine the source of your fever and constipation, and then treatment will proceed from there. Often, patients are able to be treated at home after seeking a medical opinion, but severe cases can require a hospital stay or surgery.

The bottom line here: Fever and constipation can occur at the same time—but it doesn't necessarily mean constipation caused your fever. Instead, having both symptoms simultaneously usually means there's another underlying issue. The most important thing to do in that situation is not to delay treatment—check in with a doctor ASAP so they can figure out what's going on.

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