Sertraline Diarrhea: What It Is, Why It Happens, and How to Manage It

When you start taking sertraline, a selective serotonin reuptake inhibitor (SSRI) used to treat depression, anxiety, and OCD. Also known as Zoloft, it works by increasing serotonin levels in your brain—but that same boost can stir up your gut. Diarrhea is one of the most common side effects, affecting up to 20% of people in the first few weeks. It’s not rare. It’s not a sign you’re doing something wrong. It’s just how your body adjusts.

Why does this happen? Serotonin isn’t just a brain chemical. About 95% of your body’s serotonin lives in your intestines, where it helps control bowel movements. When sertraline floods your system with extra serotonin, your gut gets overstimulated. That means faster contractions, less water absorption, and looser stools. It’s not an infection. It’s not food poisoning. It’s a direct result of the drug’s mechanism. This isn’t unique to sertraline—other SSRIs like fluoxetine and escitalopram can do the same thing—but sertraline seems to trigger it more often than most.

Most people find the diarrhea fades within 1–4 weeks as their body adapts. But for some, it sticks around longer. If it’s mild, try eating smaller meals, avoiding spicy or fatty foods, and staying hydrated. Probiotics might help, though evidence is mixed. If it’s severe, lasts more than a month, or comes with weight loss or dehydration, talk to your doctor. Don’t stop sertraline on your own. Stopping suddenly can cause withdrawal symptoms like dizziness, nausea, and even more digestive upset. Your doctor might lower your dose temporarily, switch you to a different SSRI, or add a medication like loperamide to help.

Many people don’t realize that SSRI side effects, a group of common reactions to antidepressants that target serotonin often overlap with other medications. For example, if you’re also taking antibiotics, drugs that kill bacteria but can also disrupt gut flora, your diarrhea could be worse. The same goes for calcium supplements, which can interfere with how your body absorbs certain drugs. Even something as simple as drinking too much coffee can make it worse. It’s not just the sertraline—it’s how it plays with everything else in your system.

What you’ll find in the posts below are real, practical stories and science-backed advice from people who’ve been there. You’ll see how others handled it, what worked, what didn’t, and how to tell if it’s just a side effect or something more serious. There’s no fluff—just clear, no-nonsense info to help you decide what to do next. Whether you’re just starting sertraline or have been on it for months and still struggle with digestion, you’ll find something that helps.