About diarrhea

    Diarrhea: Causes, What It Is, and How to Manage It

    Learn what diarrhea means, common causes, and when to worry about symptoms that need medical attention.

    Diarrhea is passing loose, watery stools more often than usual. It can happen when your intestines move too fast or when they release extra fluid. The exact cause varies by person, and your gut microbiome can influence how strongly your gut reacts to triggers like food or infections.

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    How diarrhea works

    Diarrhea usually starts when something irritates the gut lining or changes how the bowel moves. This can speed up transit, so water isn’t absorbed well. The result is looser, more frequent stools.

    Some causes also increase fluid or inflammation in the intestines. For example, infections can disrupt the lining and trigger immune signals. That can pull more water into the gut and make stools watery.

    Your gut microbiome also plays a role. Helpful bacteria help break down fibers and support the gut barrier. When the microbiome is disturbed, the gut may become more reactive and recovery can take longer.

    Why it matters for your health

    Diarrhea can lower your energy quickly because you lose fluids and electrolytes like sodium and potassium. Dehydration can cause dizziness, weakness, and fast heartbeat.

    It may also disrupt digestion and metabolism. When food moves too fast, your body has less time to absorb nutrients, including carbohydrates and minerals.

    Most short cases pass without long-term problems, but prolonged or severe diarrhea can lead to weight loss, ongoing gut irritation, and nutrient gaps. In some cases, it can also increase the risk of complications, especially for older adults or people with weak immune systems.

    What affects diarrhea?

    - Food and drink: Spicy foods, high-fat meals, alcohol, and certain additives may trigger loose stools.
    - Food intolerance: Lactose or other sensitivities can cause recurring diarrhea.
    - Gut microbiome: Imbalance after illness or antibiotics can reduce gut barrier strength.
    - Infection exposure: Viruses, bacteria, and parasites often cause sudden diarrhea.
    - Stress and sleep: Poor sleep and chronic stress can change gut motility and inflammation.
    - Medications: Antibiotics, metformin, and some laxatives can affect stool consistency.
    - Medical conditions: IBS, IBD, celiac disease, and other conditions can lead to ongoing symptoms.
    - Biological factors: Age, hydration status, and immune response influence severity.

    Why it differs per person

    Two people can eat the same food and respond differently. Your gut microbiome varies from person to person, which can change how your gut handles irritation and infection.

    Genetics and past health also matter. Some people have a gut lining that’s more sensitive, while others recover faster because their gut ecosystem is more resilient.

    Lifestyle differences play a role too. Stress levels, sleep quality, and recent antibiotic use can shift gut bacteria and affect how fast your intestines move.

    2-minute self-check Is a gut microbiome test useful for you? Answer a few quick questions and find out if a microbiome test is actually useful for you. ✔ Takes 2 minutes ✔ Based on your symptoms & lifestyle ✔ Clear yes/no recommendation Check if a test is right for me
    If diarrhea keeps coming back—or feels unpredictable—it can help to understand what’s happening in your gut. A gut microbiome test can offer clues about balance and recovery support, which may guide more personalized nutrition choices with your clinician’s input.

    Diarrhea: What It Is, Causes, and When to Worry

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