Last Updated on August 19, 2025 by Beth Skwarecki
Ever grabbed some Mylanta for heartburn relief and suddenly found yourself making unexpected trips to the bathroom? You’re definitely not alone in this experience. Let’s learn about what’s actually happening when Mylanta makes you poop and why this side effect catches so many people off guard.
The Quick Answer: Yes, Mylanta Can Make You Poop
Here’s the deal: Mylanta absolutely can make you poop, and there’s a pretty straightforward reason for it. The culprit? Magnesium. This key ingredient in Mylanta doesn’t just neutralize stomach acid—it also has some serious laxative properties that can get your digestive system moving faster than you expected.
You know how some people take magnesium supplements specifically for constipation? Well, Mylanta contains magnesium hydroxide, which is basically the same stuff found in milk of magnesia and other laxatives. So when you’re treating your heartburn, you’re accidentally dosing yourself with a bowel stimulant too.
What’s Actually Inside Mylanta?
Different Mylanta products contain slightly different ingredients, but most include:
- Aluminum hydroxide – helps neutralize acid but can cause constipation
- Magnesium hydroxide – neutralizes acid AND acts as a laxative
- Simethicone – reduces gas and bloating
The magnesium is doing double duty here. It’s tackling your stomach acid while simultaneously encouraging bowel movements. Pretty efficient, right? 🙂
How Much Magnesium Are We Talking About?
The amount of magnesium varies between different Mylanta formulations. Some products pack more magnesium punch than others, which explains why some people experience more pronounced digestive effects.
Maximum strength versions typically contain higher magnesium levels, which means they’re more likely to send you running to the bathroom. One doctor on HealthTap specifically noted that maximum strength Mylanta contains enough magnesium to trigger bowel movements in many users.
When Does This Bathroom Rush Usually Happen?
Most people notice the laxative effect within a few hours of taking Mylanta. Some folks report waking up with diarrhea after taking it before bedtime (definitely not the way you want to start your morning).
The timing depends on several factors:
- How much you took
- Your individual sensitivity to magnesium
- Whether you took it on an empty or full stomach
- Your overall digestive health
Is This Normal or Should You Worry?
Here’s some reassurance: experiencing diarrhea from Mylanta is completely normal. It’s not dangerous, and it doesn’t mean something’s wrong with you or the medication. It’s simply your body responding to the magnesium content.
However, you should pay attention if:
- The diarrhea is severe or persistent
- You’re becoming dehydrated
- You experience other concerning symptoms
Managing the Mylanta Poop Problem
If Mylanta’s laxative effect is cramping your style (pun intended), here are some strategies:
Switch to Lower-Magnesium Options
Look for antacids that contain more aluminum and less magnesium. Aluminum actually has the opposite effect—it can cause constipation. Some antacids balance these ingredients specifically to minimize both constipation and diarrhea.
Try Calcium-Based Antacids Instead
Products like Tums use calcium carbonate instead of magnesium. These are less likely to cause digestive upset, though they might not work as quickly for some people.
Adjust Your Timing
Taking Mylanta with food might slow down the magnesium absorption and reduce the laxative effect. Some people find this helps minimize bathroom emergencies.
Stay Hydrated
If you do experience diarrhea, make sure you’re drinking plenty of fluids to prevent dehydration. This is especially important if you’re taking Mylanta regularly.
The Aluminum vs. Magnesium Balancing Act
Here’s something interesting: many antacid manufacturers try to balance aluminum and magnesium specifically because of their opposing effects on bowel movements. Aluminum tends to cause constipation, while magnesium promotes loose stools.
The idea is that these effects cancel each other out, leaving you with acid relief without digestive drama. But everyone’s body responds differently, and some people are more sensitive to the magnesium component.
Who’s Most Likely to Experience This?
Certain groups of people might be more prone to Mylanta’s laxative effects:
- People with sensitive digestive systems
- Those taking higher doses or maximum strength formulations
- Individuals with kidney problems (they can’t clear magnesium as efficiently)
- Regular users who take Mylanta frequently
Other Possible Side Effects of Mylanta
While Mylanta is generally well-tolerated, some individuals may experience other side effects aside from its laxative effects. These may include:
- Nausea or vomiting: Some people might feel queasy or experience mild stomach discomfort.
- Allergic reactions: Rarely, individuals may develop symptoms such as itching, rash, or swelling of the throat or tongue.
- Abdominal cramping: Digestive discomfort can sometimes occur, especially with higher doses.
- Changes in stool consistency: Loose or softened stools are common but should be monitored if they persist.
- Fatigue or weakness: Although uncommon, some may feel tired or weak due to imbalances in magnesium or other electrolytes.
If any of these symptoms become severe or persistent, it’s important to consult a healthcare provider promptly for further evaluation.
When to Talk to Your Doctor
While the occasional bout of Mylanta-induced diarrhea isn’t concerning, you should check with your healthcare provider if:
- You need antacids frequently (this could indicate an underlying condition)
- The diarrhea is severe or doesn’t improve after stopping Mylanta
- You have kidney problems and are considering regular antacid use
- You’re experiencing other unusual symptoms
Alternative Solutions for Heartburn Relief
If Mylanta’s bathroom side effects are too disruptive, consider these alternatives:
Other OTC Options
- Tums (calcium-based, less likely to cause diarrhea)
- Aluminum-only antacids (may cause constipation instead)
- H2 blockers like Pepcid (different mechanism, fewer GI side effects)
Lifestyle Changes
Sometimes addressing the root cause works better than treating symptoms:
- Eat smaller, more frequent meals
- Avoid trigger foods (spicy, fatty, acidic items)
- Don’t lie down immediately after eating
- Maintain a healthy weight
FAQs
The Bottom Line on Mylanta and Bowel Movements
So, does Mylanta make you poop? Absolutely, and now you know exactly why. The magnesium content is doing its job neutralizing acid, but it’s also stimulating bowel movements as an unintended side effect.
This isn’t a bug in the system—it’s just how magnesium works in your body. Some people actually appreciate this dual action, especially if they struggle with both heartburn and constipation. Others find it inconvenient and prefer alternatives.
The good news is that you have options. Whether that means switching to a different antacid, adjusting your dosing, or exploring other heartburn management strategies, you don’t have to choose between acid relief and digestive comfort.
Remember, occasional antacid use is generally safe for most people. But if you’re reaching for Mylanta (or any heartburn medication) regularly, it’s worth having a conversation with your healthcare provider about what might be causing your symptoms and whether there are better long-term solutions.
Understanding how your medications work—including their unexpected effects—helps you make better choices about your health. Now you can use Mylanta with full knowledge of what to expect, bathroom breaks and all.
Beth is Cloudmineinc’s senior health editor and a certified personal trainer. She has over 10 years experience as a science journalist and is the author of two books. She deadlifts over 315 lbs.