Does apple cider vinegar cause diarrhea, bloating or gas?

No trial we've found has isolated diarrhea, bloating, gas or constipation as a measured outcome of apple cider vinegar. A 2020 systematic review of the safety literature found the overall risk of side effects at recommended amounts appears low, but that's a general safety conclusion, not a specific answer about digestive symptoms.

What's actually been studied

The 2020 systematic review searched four databases and found 13 human studies and 12 animal studies on apple vinegar's safety and metabolic effects. Its conclusion on side effects was that the risk, at recommended amounts, appears low — but the review didn't break that finding down by specific symptom, and it rated the overall evidence base, safety included, too limited for firm conclusions either way. Mild gastrointestinal upset is the side effect most commonly mentioned across the wider apple cider vinegar literature, but "commonly mentioned" and "measured in a controlled trial" aren't the same thing here.

If your capsule also contains a prebiotic fiber

Some apple cider vinegar capsules, ours included, pair the vinegar powder with a small amount of inulin, a prebiotic fiber. Inulin and similar fibers have real, documented gastrointestinal effects in people — a 2022 review synthesizing 103 clinical trials on non-digestible fibers found that gas, bloating and stool changes are dose-dependent and fiber-specific, with tested doses across that research ranging from under 1 gram to over 100 grams a day. Our capsule's inulin content is 200 mg per serving, a small fraction of the several-gram doses that research generally covers, so it's a less likely explanation than it might sound — but a possible one worth knowing about if you're otherwise a sensitive responder to added fiber.

Liquid on an empty stomach vs. a capsule with water

A lot of the "does it upset your stomach" concern online is about drinking undiluted liquid vinegar, often on an empty stomach — a direct-acid exposure that a capsule doesn't reproduce, since the powder is contained until it reaches the stomach and our label directs it with 6-8 oz of water. No trial has directly compared digestive tolerance between the two formats, so we can't tell you a capsule is gentler as a matter of research — only that it's a different exposure, which is a different question than the one most of this literature addresses.

What the research doesn't cover

We haven't found a dedicated trial testing apple cider vinegar for nausea relief, the way some other ingredients — ginger, for instance — have their own nausea-specific research. If nausea is your main concern, that's a gap in what apple cider vinegar's evidence covers, not something this product is positioned to address. See apple cider vinegar side effects for the fuller documented picture, including some rarer effects reported at high, long-term intakes.

Questions people ask

Can apple cider vinegar make you poop?

No trial has measured a laxative or stool-frequency effect from apple cider vinegar specifically. If a capsule also contains a fiber like inulin, fiber in general is a more established influence on stool frequency than vinegar itself — see the inulin section above for the dose comparison.

Does apple cider vinegar give you gas or make you pass gas?

Not something we've found isolated in a trial for the vinegar itself. A prebiotic fiber ingredient in the same capsule is the more likely candidate at typical fiber doses, though our own capsule's fiber amount is well below the doses studied for that effect.

Can apple cider vinegar cause acid reflux or heartburn?

We haven't found a trial testing this directly. Liquid vinegar is acidic by nature, which is a plausible reason some people report reflux-like symptoms after drinking it undiluted; a capsule taken with water is a different exposure that hasn't been studied on this specific point either.

Does apple cider vinegar help an upset stomach or nausea?

We haven't found dedicated research testing apple cider vinegar for nausea or general stomach upset relief. That's different from some other ingredients that do have nausea-specific trials.

Related reading: apple cider vinegar side effects, who should not take apple cider vinegar, and is it safe to take apple cider vinegar every day.