Last Updated on April 25, 2026 by Beth Skwarecki
Yes, Mylanta can cause constipation in some people. I would say this is less expected than diarrhea, but it can happen because some Mylanta products contain aluminum hydroxide, which may slow digestion and harden stool.
Your body may react more to aluminum than magnesium.
Why Mylanta Can Cause Constipation
Aluminum hydroxide is the ingredient most linked to constipation.
It can slow bowel movement and make stool harder to pass. Some people notice fewer bowel movements, harder stool, or mild straining after taking Mylanta.
Magnesium may loosen stool, but aluminum may do the opposite.
Some people get loose stool, while others get constipation, so I recommend reading my full guide on Mylanta bowel changes.
Why One Person Gets Diarrhea And Another Gets Constipation
Mylanta can affect people differently because it contains ingredients that can pull digestion in opposite directions.
- Magnesium may loosen stool causing Diarrhea.
- Aluminum may slow stool.
- Your body may respond more strongly to one than the other.
What Constipation After Mylanta Feels Like
You may notice
- harder stool
- less frequent bowel movements
- bloating
- mild cramping
- straining
If constipation is mild, it may improve after stopping the product.
What To Do
If Mylanta seems to slow your digestion, drink enough water and avoid taking more than directed.
You may also want to review Mylanta Side Effects to compare constipation with other common reactions.
Bottom Line
Mylanta can cause constipation because aluminum hydroxide may slow digestion. Your body may react more to aluminum than magnesium, which is why bowel changes can vary from person to person.
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.