Slowing down ileostomy output comes down to three things: what you eat, how you drink, and in some cases, medication. Most people with a new ileostomy produce between 500 and 800 ml of output per day once things settle, but output regularly exceeding 1,000 to 1,500 ml per day can lead to dehydration, electrolyte imbalances, and kidney strain. The good news is that dietary changes alone make a noticeable difference for many people, and there are effective medical options when food isn’t enough.
Foods That Thicken Output
Soluble fiber absorbs water in the gut and turns loose output into a thicker, more paste-like consistency. The most reliable thickening foods are ones you probably already have in your kitchen:
- White rice and white pasta
- Mashed potatoes and pumpkin
- White bread or toast
- Bananas and applesauce
- Porridge or oats
- Smooth peanut butter
Notice the pattern: these are low-residue, starchy foods that absorb fluid as they move through your small intestine. Eating them at every meal creates a baseline of thicker output throughout the day. You don’t need to eat only these foods, but building meals around at least one or two of them helps considerably.
Psyllium husk is another effective option. Mixing one teaspoon of psyllium husk or a product like Metamucil into a cup of water and drinking it quickly before it gels can thicken output from the inside. Some people take this before meals, others between meals. Experiment with timing to see what works best for your body.
The Marshmallow Trick
This one sounds like an old wives’ tale, but it was actually tested in a randomized crossover trial published in Colorectal Disease. Participants ate three marshmallows three times a day for a week, then went a week without them. The gelatin in marshmallows thickens small bowel fluid, which is the same principle behind soluble fiber but in candy form. It’s not a cure-all, but it’s a low-risk, inexpensive strategy worth trying alongside other dietary changes.
Foods That Increase Output
Just as important as what thickens output is knowing what makes it worse. High-sugar foods and drinks pull water into the intestine through osmosis, increasing both the volume and speed of output. Fruit juices, sodas, sweets, and anything with sugar alcohols (common in “sugar-free” products) are frequent culprits. Spicy foods, raw vegetables, high-fiber fruits with skin, caffeine, and alcohol can all speed transit as well.
Keeping a simple food diary for a week or two helps you identify your personal triggers. Everyone’s gut responds a little differently, especially depending on how much small bowel you have remaining.
How You Drink Matters
This is one of the most counterintuitive parts of managing an ileostomy: drinking large volumes of plain water can actually increase output. Water is hypotonic, meaning it has a lower concentration of salts than your intestinal fluid. When you flood the gut with plain water, your body pulls it through quickly rather than absorbing it, and much of it ends up in your bag rather than hydrating you.
The more effective approach is to separate drinking from eating. Limit fluid intake for 30 minutes before and after meals, and sip slowly rather than gulping. This gives solid food time to absorb fluid in the gut without being flushed through.
For the fluids themselves, an oral rehydration solution with the right sodium concentration gets absorbed far more efficiently than water alone. Your small intestine absorbs sodium and water together when glucose is present, so the combination of salt, sugar, and water in the right proportions is key.
St. Mark’s Solution for Hydration
St. Mark’s Solution is the gold standard oral rehydration drink for people with high ileostomy output. It was developed specifically for this purpose, and the recipe is simple enough to make at home. For one liter of cold tap water, dissolve:
- Glucose powder: 20 grams (about six level teaspoons)
- Sodium bicarbonate (baking soda): 2.5 grams (one full half-teaspoon measure)
- Sodium chloride (table salt): 3.5 grams (about one level teaspoon)
The sodium concentration in this solution is designed to match the roughly 90 to 120 mmol/L that your small bowel needs for efficient absorption. If the taste is too bitter, you can swap the baking soda for the same amount of sodium citrate. Sip this throughout the day rather than drinking large amounts at once. Many people find that replacing some or all of their plain water intake with this solution reduces output volume noticeably within a few days.
Ileostomy fluid itself contains about 100 mmol of sodium per liter, so when output is high, you’re losing substantial amounts of salt. This is why plain water doesn’t replenish what you’re losing, and why people with high-output stomas can feel dehydrated even when they’re drinking plenty.
Medication Options
When dietary changes and rehydration aren’t enough, loperamide (the active ingredient in Imodium) is the first-line medication. It works by slowing the muscular contractions of the intestine, giving your gut more time to absorb water from its contents. The standard maximum dose listed on over-the-counter packaging is 16 mg per day, but people with ileostomies often need more than this because the drug itself is less well absorbed without a full colon.
For high-output stomas, clinicians routinely prescribe doses well above 16 mg. Published case reports describe patients on 90 mg, 300 mg, and even 400 mg daily using specially compounded capsules, with no significant side effects and normal kidney and liver function on follow-up years later. These high doses are only used under medical supervision, but the point is important: if a standard dose of loperamide isn’t working for you, there is significant room to increase it safely with your care team’s guidance.
Timing matters too. Taking loperamide 30 to 60 minutes before meals gives it time to slow the gut before food triggers another wave of contractions. Some people split their dose across three or four times a day rather than taking it all at once.
Second-Line Options
If loperamide alone isn’t sufficient, doctors may add a proton pump inhibitor, which reduces the volume of digestive secretions your stomach produces. This can meaningfully lower total output volume because a surprising amount of stoma output is actually digestive fluid, not just food residue. For the most severe cases, an injectable medication called octreotide can reduce intestinal secretions further, though it’s typically reserved for situations where other options have failed due to the discomfort of injections and a long-term association with gallstone risk.
Signs of Dehydration to Watch For
Dehydration is the biggest risk of persistently high output, and it can develop faster than you’d expect. The warning signs to pay attention to are dark or concentrated urine, producing very little urine, dizziness when standing up, a racing heart, persistent thirst, dry mouth, and feeling unusually tired or confused. Muscle cramps, especially in the legs, can signal low sodium or potassium.
Dehydration from high ileostomy output is one of the most common reasons for hospital readmission after stoma surgery. It tends to compound: once you’re behind on fluids, the gut absorbs even less efficiently, output stays high, and the cycle worsens. If you notice these symptoms developing and can’t stay ahead of them with oral rehydration, that situation needs medical attention promptly. Catching it early, before kidney function is affected, makes recovery much simpler.
Putting It All Together
The most effective approach combines several strategies at once rather than relying on any single one. Build meals around starchy, low-residue foods. Add psyllium husk or marshmallows if you want an extra thickening boost. Replace plain water with St. Mark’s Solution or a similar glucose-saline drink, and sip it between meals rather than during them. If output is still too high, talk to your stoma nurse or gastroenterologist about loperamide dosing, because the over-the-counter dose is often just a starting point for people with ileostomies. Track your output volume for a few days so you have real numbers to share with your care team, as this makes it much easier to adjust the plan.