Why Do I Keep Getting Diarrhea On And Off?

Loose stools that come and go for weeks are usually a sign that something keeps irritating your gut or that your gut is having trouble absorbing food properly. The most common culprits are diet, medications, infections that never fully cleared, and chronic conditions like irritable bowel syndrome or inflammatory bowel disease. Intermittent diarrhea is different from a one-time stomach bug — the pattern itself is a clue your doctor will want to know about.

Why Do I Keep Getting Diarrhea On And Off?

The pattern matters more than any single episode. Diarrhea that returns in cycles usually points to one of a few categories of causes, and figuring out which category you fall into is the first real step.

Doctors generally define diarrhea as loose or watery stools occurring three or more times in a day. When it lasts less than four weeks, it is called acute. When it stretches past four weeks, it is called chronic. The on-and-off pattern you are describing often sits somewhere in between — recurring acute episodes, or a chronic condition that flares and settles.

Common categories include:

• Dietary triggers — lactose, artificial sweeteners like sorbitol and mannitol, caffeine, alcohol, or large amounts of spicy or fatty food
• Medications — antibiotics, magnesium-containing antacids, some blood pressure drugs, certain antidepressants, and many others
• Infections — bacterial, viral, or parasitic infections that either linger or keep returning
• Food intolerances and malabsorption — including lactose intolerance and problems absorbing certain sugars
• Chronic conditions — irritable bowel syndrome (IBS), inflammatory bowel disease (IBD), celiac disease, and bile acid malabsorption
• Stress and gut-brain signaling — the gut and brain communicate constantly, and stress can change how fast food moves through your system

Notice that most of these are not emergencies. But a few — like IBD or a persistent infection — need medical attention. The rest of this article will help you sort through the possibilities without guessing.

What Is the Difference Between IBS and Inflammatory Bowel Disease?

These two get confused constantly, and the confusion matters because they are very different conditions.

Irritable bowel syndrome is a functional disorder. The gut looks normal on standard tests, but it does not work normally. The muscles and nerves of the bowel behave differently, causing cramping, bloating, and alternating diarrhea and constipation. IBS does not cause visible damage to the intestine and does not raise your risk of colon cancer.

Inflammatory bowel disease is a group of conditions — Crohn’s disease and ulcerative colitis being the main ones — where the immune system attacks the lining of the digestive tract. This causes real inflammation, ulcers, and sometimes bleeding. IBD can lead to serious complications if untreated.

Some signs that point more toward IBD than IBS include:

• Blood or mucus in your stool
• Unintentional weight loss
• Fever
• Diarrhea that wakes you from sleep
• Anemia found on blood tests

If you have any of these, see a doctor rather than assuming it is IBS. IBS is common and manageable, but IBD needs medical treatment and monitoring.

Could a Food Intolerance Be Causing My Recurring Diarrhea?

Food intolerances are one of the most common reasons diarrhea keeps coming back, and they are easy to miss because reactions can be delayed.

Lactose intolerance is the classic example. If your body does not make enough lactase — the enzyme that breaks down lactose — undigested lactose sits in your intestine, draws in water, and gets fermented by gut bacteria. The result is gas, bloating, and loose stools, often within a few hours of eating dairy. Lactose intolerance is more common in adults of East Asian, African, Hispanic, and Native American descent, though it can affect anyone.

Other common triggers include:

• Sugar alcohols — sorbitol, mannitol, xylitol, and erythritol, found in sugar-free gum and diet foods
• Fructose — especially in large amounts from fruit juice or high-fructose corn syrup
• Caffeine and alcohol — both stimulate the bowel
• Spicy or very fatty foods — these can speed up digestion in sensitive people

The tricky part is that a food can cause diarrhea one day and not the next, depending on how much you ate and what else was in your system. This is why keeping a simple food and symptom diary for a couple of weeks can be genuinely useful. It is not a diagnosis, but it gives your doctor real information to work with.

Can Medications Cause Diarrhea That Comes and Goes?

Yes, and this is one of the most overlooked causes. Many people do not connect a new medication to gut symptoms because the diarrhea starts days or even weeks after the first dose.

Antibiotics are the best-known offender. They kill off some of the normal gut bacteria along with the infection, which can lead to diarrhea during the course and sometimes for weeks afterward. In some cases, a bacterium called Clostridioides difficile overgrows and causes persistent diarrhea that needs specific treatment. This is more likely after antibiotics, in older adults, and in people who have been in hospitals or care facilities.

Other medications linked to diarrhea include:

• Magnesium-containing antacids and laxatives
• Some blood pressure medications, including ACE inhibitors
• Certain antidepressants, particularly SSRIs
• Metformin, used for type 2 diabetes
• NSAIDs like ibuprofen and naproxen
• Some cancer treatments and immunosuppressants

Do not stop a prescribed medication on your own. Talk to your prescriber about whether a dose change or a different drug might help. Many times, the diarrhea is manageable without giving up the treatment.

When Should I See a Doctor About On-and-Off Diarrhea?

Most short bouts of diarrhea resolve on their own. But recurring episodes deserve a medical look, especially if they have lasted more than a few weeks or keep returning.

See a doctor promptly if you notice any of the following:

• Blood or black, tarry stools
• Signs of dehydration — dark urine, very dry mouth, dizziness on standing
• Unintentional weight loss
• Fever that keeps coming back
• Diarrhea that wakes you from sleep
• Severe abdominal pain
• Symptoms that started after travel to another country
• Diarrhea lasting more than two days in a child, or more than a week in an adult

Your doctor will likely ask about your diet, medications, travel history, and family history. They may order stool tests, blood tests, or refer you for a colonoscopy or endoscopy if they suspect inflammation or malabsorption. These tests are not as scary as they sound, and they often give clear answers.

One useful thing to know: a colonoscopy is not automatically needed for every case of intermittent diarrhea. If your symptoms fit IBS and you have no warning signs, many doctors will treat it without invasive testing first. Guidelines generally recommend colonoscopy for people with warning signs or those over a certain age who have not had screening.

What Role Does Stress Play in Recurring Diarrhea?

Stress does not cause diarrhea out of nowhere, but it can absolutely make an existing gut problem worse.

Your gut has its own nervous system — sometimes called the enteric nervous system — that talks directly to your brain. When you are stressed, your body releases hormones that can speed up or slow down digestion, change how sensitive your gut is to pain, and alter the balance of bacteria in your colon. For people with IBS, this gut-brain connection is a central part of the condition.

This does not mean your symptoms are “all in your head.” The physical changes are real. But it does mean that managing stress can be part of managing your gut. Some research suggests that cognitive behavioral therapy and gut-directed hypnotherapy can reduce IBS symptoms in some people, though results vary and these approaches work best alongside standard care, not instead of it.

Simple things that may help include regular sleep, gentle exercise, and eating at consistent times. These are not cures. They are supports.

What Can I Do to Manage Intermittent Diarrhea?

Management depends on the cause, so the first step is always figuring out what is driving your symptoms. That said, some general approaches are reasonable while you and your doctor work on a diagnosis.

Diet changes that often help:

• Reduce or avoid caffeine, alcohol, and artificial sweeteners
• Try a temporary low-FODMAP diet only under medical supervision — it is not meant to be permanent
• Eat smaller, more frequent meals instead of large ones
• Stay hydrated with water and electrolytes, especially during episodes

Over-the-counter options like loperamide can slow the bowel and reduce diarrhea, but they should not be used if you have bloody stools or a suspected infection. They are not a treatment for the underlying cause.

Probiotics are often marketed for diarrhea, but the evidence is mixed. Some strains may help with antibiotic-associated diarrhea, while others show no clear benefit. No single probiotic is proven to fix intermittent diarrhea in everyone, and the FDA does not regulate them the same way it regulates drugs.

What works best is a clear diagnosis. Once you know whether you are dealing with IBS, a food intolerance, a medication side effect, or something else, treatment becomes much more targeted — and much more likely to work.