8 Supplements to Be Careful With if You Have Crohn’s Disease
Published on September 23, 2026
The supplement aisle can sometimes be an overwhelming place, especially when you have Crohn’s disease. While certain people with Crohn’s may benefit from taking a well-chosen supplement on the advice of their doctor or registered dietitian, certain pills, powders, shakes, and chewables may also come with downsides.
“When referring to herbs or supplements, natural does not mean they are safer; in many cases, the opposite could be true,” says Berkeley Limketkai, MD, PhD, the director of clinical research at the UCLA Health Center for Inflammatory Bowel Diseases in Los Angeles. What’s more, it’s possible that certain products could cause gastrointestinal (GI) discomfort or make your symptoms worse.
Here’s a look at eight supplements that people with Crohn’s may need to steer clear of.
1. Laxative Herbs
Crohn’s-related constipation can be frustrating. But you should talk with your gastroenterologist before taking an herbal laxative like senna, cascara, or aloe latex if you’re having trouble passing a bowel movement, for a few reasons.
First, it’s possible that your constipation could be caused by a serious Crohn’s complication, like a bowel obstruction, which requires medical treatment. In that case, trying to self-treat with a laxative won’t help and could make the problem worse, says Aditi Stanton, MD, a gastroenterologist with GastroHealth in Cincinnati.
While certain laxatives might be an option for constipation that isn’t due to a blockage, herbal products may not be the best choice because they can cause intense cramping, nausea, and diarrhea. There hasn’t been enough research on aloe latex to confirm its safety, and some research has suggested that compounds in it may cause cancer.
2. High-Dose Vitamin C
Vitamin C is sometimes used to support a strong immune system during cold and flu season. While those benefits aren’t proven, experts know that taking too much of the vitamin — generally more than 2,000 milligrams per day — can trigger or worsen GI symptoms that you might already be dealing with, like stomach cramps and loose stool.
Beyond the potential discomfort, there’s another reason to be cautious: If you’re having GI issues while taking vitamin C (or another supplement), it can be harder for you and your care team to figure out whether the issues are actually related to the supplement or if your Crohn’s is flaring or getting worse, Dr. Limketkai says.
3. Magnesium
It’s not uncommon to be deficient in magnesium when you have Crohn’s. But like vitamin C, magnesium can upset your GI tract and may add to all-too-familiar symptoms like diarrhea and nausea.
The effect is more common with certain types of magnesium, like magnesium citrate and oxide. Magnesium glycinate, on the other hand, may be less likely to cause GI symptoms. But if you’re thinking of supplementing with any form of magnesium, you should talk it over with your gastroenterologist first. “The right dose depends on blood tests, diet, disease location, prior bowel surgery, symptoms, and current treatment,” Dr. Stanton says.
4. Oral Iron Supplements
Iron is another mineral that can be hard for many people with Crohn’s to get enough of. If you’ve had blood tests that show you’re deficient, hold off on buying iron pills. Your gastroenterologist may recommend iron infusions instead.
First and foremost, pills aren’t as effective as infusions at bringing your iron level back up. “Especially when inflammation is active with Crohn's disease, oral iron absorption can be compromised and replenishes deficient iron stores less effectively than intravenous iron,” says Limketkai.
Oral iron can also cause uncomfortable side effects like nausea, diarrhea, constipation, and abdominal pain. “Moreover, oral iron darkens stool, which can mask the presence of GI bleeding, which can also appear as dark or black stool,” Limketkai says.
5. Fiber Supplements
It’s great to get fiber in your diet whenever you’re able to tolerate it, since it can support gut health and actually help keep your Crohn’s symptoms under control. But the preferred way to get your fill is from whole foods like fruits and vegetables, whole grains, and beans or other legumes, such as lentils.
“Taking a supplement might make you bloated or cause gas or cramping,” says Supriya Rao, MD, a gastroenterologist with Tufts Medicine in Lowell, Massachusetts.
And depending on your Crohn’s severity, symptoms, and any complications you have (such as strictures), you may need to reach for certain types of fiber or to modify the texture of fiber-rich foods. Supplementing might make sense if you need help getting the recommended 25 to 34 grams of fiber per day. In that case, talk with your gastroenterologist to figure out the right product for you. Dr. Rao usually suggests psyllium husk to her patients, since it’s well studied and less likely to cause GI symptoms than other fiber supplements.
6. Probiotics
There are lots of good reasons to enjoy probiotic-rich foods like yogurt, tempeh, miso, and sauerkraut. But there’s no solid evidence that probiotic supplements can help control your Crohn’s, and they could cause side effects like abdominal pain, gas, and bloating.
“For Crohn’s disease, probiotic supplements have not been shown to reliably induce or maintain remission, or to prevent relapse,” Stanton says.
In rare instances, taking a probiotic could lead to serious infection. The chances are higher if you’re flaring or if you’re taking a Crohn’s medication that suppresses your immune system, says Stanton.
7. Immune-Boosting Herbs
Avoid taking herbs that may claim to give your immune system extra oomph — like echinacea, astragalus, Asian ginseng, ashwagandha, and mushroom blends, to name a few — without talking to your gastroenterologist.
While there’s not much research on how immune-stimulating herbs impact people with Crohn’s, it’s possible that they could work against your prescribed treatment. “An underlying issue with the Crohn’s disease process is an overactive or hyperactive immune system, for which medical treatments are designed to calm the immune system. Taking an immune-stimulating compound does the exact opposite of what one hopes to achieve,” says Limketkai.
8. Supplements With Sugar Alcohols
Sugar alcohols like xylitol, erythritol, sorbitol, and mannitol aren’t believed to be harmful in moderation. But the sweeteners, which are often found in gummies, powders, and chewable pills, are known for triggering gas, bloating, and diarrhea. And people with Crohn’s are even more prone to experiencing discomfort after ingesting them. Fortunately, sugar alcohols are easy to spot on a product’s ingredient list, so always check before buying something new.
EDITORIAL SOURCES
Everyday Health follows strict sourcing guidelines to ensure the accuracy of its content, outlined in our editorial policy. We use only trustworthy sources, including peer-reviewed studies, board-certified medical experts, patients with lived experience, and information from top institutions.
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Amber Charoen, MD
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Amber Charoen, MD, is a triple board-certified gastroenterologist at Prosser Memorial Health in Prosser, Washington, where she provides comprehensive gastrointestinal (GI) care in ...
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