Microscopic colitis is highly treatable, and most people see significant improvement within two weeks of starting medication. The condition causes chronic watery diarrhea due to inflammation in the colon lining that’s only visible under a microscope. Treatment follows a stepwise approach: checking for medication triggers, starting a targeted steroid, and adjusting from there based on how you respond.
Check Your Medications First
Before adding a new drug, your doctor will likely review what you’re already taking. Several common medication classes are linked to an increased risk of microscopic colitis, including proton pump inhibitors (like omeprazole), SSRIs used for depression and anxiety, NSAIDs like ibuprofen and naproxen, and statins for cholesterol. NSAIDs are particularly problematic because they increase gut permeability and weaken the protective lining of the colon, allowing bacteria and irritants to trigger inflammation.
If you’re taking one of these medications and your symptoms align with when you started it, your doctor may recommend switching to an alternative. For some people, this alone resolves the diarrhea without any additional treatment. It’s worth having this conversation early, since continuing a triggering medication can make other treatments less effective.
Budesonide: The Primary Treatment
Budesonide, a steroid that works locally in the gut with fewer body-wide side effects than traditional steroids, is the standard first-line treatment. The typical starting course is 9 mg daily for six to eight weeks. In clinical trials, this regimen produced remission in 77% to 100% of patients, depending on the study, compared to just 12% to 20% for placebo. Most people notice their watery diarrhea decreasing within the first two weeks.
Budesonide works for both subtypes of microscopic colitis: collagenous colitis and lymphocytic colitis. One randomized trial found that 86% of patients with lymphocytic colitis achieved a clinical response at six weeks on budesonide, compared to 48% on placebo. For collagenous colitis, response rates were similarly strong across multiple trials.
What Happens After the Initial Course
Here’s the frustrating part: microscopic colitis tends to come back. Nearly half of patients (46.4%) experience recurrence after stopping budesonide maintenance therapy. Because of this high relapse rate, many people need a long-term low dose to keep symptoms under control.
Most patients who need maintenance do well on the lowest effective dose, typically 3 mg daily. In one population-based study, about 71% of maintenance patients stayed in remission at this dose. A smaller group (about 11%) managed with 3 mg every other day. Your doctor will likely taper the dose gradually after the initial treatment course, watching for returning symptoms to find the minimum amount that keeps your diarrhea in check.
If Budesonide Isn’t an Option
For people who can’t take budesonide, the American Gastroenterological Association recommends bismuth subsalicylate (the active ingredient in Pepto-Bismol) as an alternative. It’s available over the counter and taken at higher doses than you’d use for a typical stomach upset. While the evidence isn’t as robust as for budesonide, it can help induce remission in milder cases.
Bile acid sequestrants are another option, particularly if you have concurrent bile acid malabsorption, which affects a significant portion of microscopic colitis patients. In a study of 282 patients treated with bile acid sequestrants, about 49% had a complete response and another 16% had a partial response, putting the overall benefit rate near two-thirds. However, about 10% couldn’t tolerate the medication, and roughly 42% of those who stopped treatment saw symptoms return within a median of 21 weeks.
Treatment for Stubborn Cases
When budesonide and other standard medications fail, doctors classify the disease as steroid-refractory. At this point, biologic medications become an option. These are injectable or infusion-based drugs that target specific parts of the immune system to reduce inflammation.
A meta-analysis of 164 patients with steroid-refractory microscopic colitis found that vedolizumab, which blocks immune cells from entering the gut, achieved clinical remission in about 64% of patients, with 60% maintaining that remission over time. Infliximab, which targets a key inflammatory protein, produced remission in roughly 58% of patients, though maintenance rates dropped to about 45%. A third option, adalimumab, had the lowest response rate at around 39%. Vedolizumab also had the best safety profile, with only about 12% of patients needing to stop due to side effects, compared to 33% for infliximab.
Between biologics and budesonide, immunomodulators (drugs that broadly dial down immune activity) are sometimes tried for maintenance. These take considerably longer to work, around 10 to 12 weeks, so they’re not useful for getting symptoms under control quickly. They serve as a bridge for people who respond to budesonide initially but relapse repeatedly.
Surgery Is Rarely Needed
Surgical options exist but are considered a last resort for severe disease that hasn’t responded to any medical therapy. Procedures can include creating an ileostomy (rerouting the intestine to an external bag) or removing part of the colon. With the expanding range of effective medications, including biologics, very few people reach this point. Data on surgical outcomes is limited to individual case reports.
Dietary Changes That Help
No specific diet has been shown to heal microscopic colitis, but adjusting what you eat and drink can meaningfully reduce diarrhea symptoms while your medication takes effect. The National Institute of Diabetes and Digestive and Kidney Diseases recommends limiting or avoiding alcohol, artificial sweeteners, and caffeine, all of which can worsen watery stools.
If you have celiac disease alongside microscopic colitis (the two conditions overlap more often than chance would predict), a strict gluten-free diet is important. Similarly, if lactose intolerance is contributing to your symptoms, cutting back on milk and dairy products can help. These dietary changes work best as complements to medical treatment rather than replacements for it. Keeping a food diary for a few weeks can help you and your doctor identify which specific triggers make your symptoms worse.
What a Typical Treatment Timeline Looks Like
Most people follow a predictable path. Within the first two weeks of starting budesonide, diarrhea frequency drops noticeably. By six to eight weeks, the majority are in remission. At that point, you’ll taper the dose over several weeks. If symptoms stay away, you may be able to stop entirely. If they return during the taper or after stopping, you’ll likely settle into a low maintenance dose for months or sometimes years.
For those who need biologics, the timeline is different. Response rates at three to six weeks reach about 77%, but true remission takes longer to establish, with about 55% achieving it by 12 to 16 weeks. The overall picture, though, is reassuring: microscopic colitis responds well to treatment in the vast majority of cases, and the available options cover a wide range of severity levels.