What are the side effects of Aluminum Hydroxide?
Last updated September 7, 2026.
**Constipation is the most common side effect of aluminum hydroxide, and occasional short term use causes no other problems for most people.** Some people also notice a chalky taste, nausea, or less appetite. Combination products that pair aluminum with magnesium tend to cause less constipation, because magnesium loosens stools instead. Frequent or high dose use over weeks can lower blood phosphate, which shows up as muscle weakness, bone pain, or unusual tiredness. Aluminum hydroxide binds other medicines in your stomach, so spacing doses apart matters more than most people realize.
What to do
- Space out other medicines: Take antibiotics, levothyroxine, iron, and similar drugs at least 2 hours before or after your antacid.
- Manage the constipation: Add fluids and fiber, or switch to a product that combines aluminum with magnesium.
- Keep use short: Antacids are meant for occasional relief, so talk to a clinician if you need them most days for more than 2 weeks.
- Check your kidneys first: Tell a clinician about any kidney problem before using aluminum hydroxide regularly, since your body clears aluminum through the kidneys.
- Read the full label: Follow the maximum daily dose on the package and count every antacid product you take, since many contain the same ingredient.
- Get seen for warning signs: Black or tarry stools, vomit that looks like coffee grounds, trouble swallowing, unexplained weight loss, or chest pain need medical care right away.
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