Does milk thistle help with IBS or GERD? What the research does and doesn't show

No trial has tested milk thistle by itself for irritable bowel syndrome, inflammatory bowel disease or GERD. A 2018 retrospective study found less diarrhea in a diabetic subgroup with IBS when given a three-ingredient combination product, and a 2015 systematic review of IBD treatments lists silymarin among the herbs studied — without singling it out as one of the more strongly evidenced options.

What the evidence doesn't support

It doesn't support milk thistle or silymarin, alone, as a treatment for IBS, Crohn's disease, ulcerative colitis, GERD or acid reflux. No trial has isolated milk thistle and tested it against one of these conditions in a controlled way. Nothing here describes a specific product's dose, and nothing here is a claim about any product.

What the trials found

A 2018 retrospective study in Acta Bio-Medica looked at 59 people with type 2 diabetes and dyslipidemia who had IBS with diarrhea, diarrhea caused by metformin, or statin intolerance, all treated with a combination product containing berberine, silymarin and red yeast rice (monacolins). After six months, the treated group reported significantly less diarrhea (5 of 31 versus 22 of 28 in an untreated comparison group), alongside drops in HbA1c, total cholesterol, LDL and triglycerides. This is a retrospective analysis, not a randomized trial, and it's a three-ingredient product — berberine on its own is documented to affect gut motility, so the diarrhea result can't be attributed to silymarin, let alone milk thistle by itself.

A 2015 systematic review in the Journal of Crohn's and Colitis searched for randomized and controlled trials of complementary and alternative treatments in Crohn's disease and ulcerative colitis through March 2014. It found 26 randomized and 3 controlled trials across a list of herbal medicines that included silymarin, alongside aloe vera, curcumin, boswellia and others. The review's conclusion names plantago ovata and curcumin as more strongly evidenced in ulcerative colitis maintenance, and wormwood in Crohn's disease — silymarin isn't named among that group, though it appears in the wider list of herbs the review searched for. The review doesn't report a specific silymarin trial result to summarize here; it only confirms that silymarin has been studied as one of many CAM options in IBD, without singling out a finding.

We found no study — human, animal or lab-dish — addressing milk thistle or milk thistle tea specifically for GERD or acid reflux.

Questions people ask

Is milk thistle good for IBS?

The closest evidence is a retrospective study of a three-ingredient combination product that found less diarrhea in diabetic patients with IBS — a result that can't be credited to milk thistle by itself. No trial has tested milk thistle alone for IBS.

Is milk thistle good for IBS with diarrhea (IBS-D)?

Same evidence as above: only a combination-product study exists, and it wasn't designed to isolate silymarin's contribution.

Is milk thistle tea good for GERD?

No study addresses this. We found no trial, in any form, testing milk thistle for GERD or acid reflux.

When to talk to a doctor

Anyone with diagnosed IBS, IBD or GERD should manage it with a doctor's guidance; milk thistle is not a treatment for any of these conditions, and the research above doesn't support using it as one. If you take a prescription medication for a digestive condition, ask a doctor before adding milk thistle — see milk thistle and medications: what to check.

Related reading: does milk thistle cause diarrhea, bloating or constipation, milk thistle side effects, and what is milk thistle.