Microscopic Colitis: Symptoms, Causes, and What You Can Do

When your stomach feels fine but your bowels won’t stop, you might be dealing with microscopic colitis, a chronic inflammation of the colon that’s invisible to the naked eye but shows up clearly under a microscope. Also known as lymphocytic colitis or collagenous colitis, it’s one of the most common causes of long-term watery diarrhea in adults over 50 — and it’s often misdiagnosed as IBS. Unlike Crohn’s or ulcerative colitis, there’s no visible damage in your colon during a regular scope. The real problem hides in the tissue — immune cells pile up, or a thick collagen layer forms under the lining, messing with how your colon absorbs water. That’s why you get constant diarrhea, cramps, and urgency — even when you feel otherwise fine.

What makes microscopic colitis tricky is how many things can trigger it. NSAIDs, common painkillers like ibuprofen and naproxen are big culprits — studies show up to half of people with this condition started taking them before symptoms began. Proton pump inhibitors, medications for heartburn like omeprazole are also linked, even though they’re meant to help your stomach. Then there’s autoimmune links — people with thyroid disease, celiac, or arthritis are more likely to develop it. And while smoking doesn’t cause it directly, it makes symptoms worse and slows recovery.

You won’t find this condition with a standard stool test or colonoscopy. Diagnosis requires a biopsy — tiny tissue samples taken during a scope — and a pathologist looking under the microscope. That’s why so many people suffer for months or years before getting the right answer. Once diagnosed, treatment is usually simple: stop the triggers (NSAIDs, PPIs), try bismuth subsalicylate (Pepto-Bismol), or use anti-inflammatory drugs like budesonide, which targets the colon without flooding your whole body with steroids. For some, dietary tweaks help — cutting caffeine, dairy, or artificial sweeteners can reduce flare-ups.

What you’ll find below are real, practical guides from people who’ve been there. From how to track your meds to avoid worsening symptoms, to understanding why certain drugs interact with your gut, to learning how to simplify your daily routine when you’re constantly rushing to the bathroom. These aren’t theory pieces — they’re tools for living with a condition that no one talks about but affects thousands.