Aluminum/magnesium hydroxide: uses, dosing, side effects
Last updated September 7, 2026.
**Aluminum hydroxide and magnesium hydroxide are antacids that relieve occasional heartburn and acid indigestion.** They neutralize acid already in your stomach. Talk to a doctor before using them if you have kidney disease, because magnesium and aluminum can build up.
What does it treat?
You can use this medicine for occasional burning after meals, sour stomach, or upset stomach caused by acid. Frequent symptoms need assessment for reflux or another cause. Some combination products add simethicone for gas; check the active ingredients because products sold under the same brand can differ.
How do you take it?
It comes as liquid and chewable tablets. For MAG-AL liquid containing 200 mg of each ingredient per 5 mL, the label directs adults and children 12 and older to take 10 to 20 mL four times daily, with a maximum of 80 mL in 24 hours. Shake and measure with a medicine cup. This label does not require food. Chew tablets fully and follow with water; their dose depends on the product. For scheduled use, take a missed dose when remembered unless the next is nearly due; never double it. Stop and call a doctor if symptoms last longer than 2 weeks; do not use the maximum dose beyond 2 weeks without supervision.
Side effects to know
- Common: You may notice a chalky taste, constipation, or diarrhea, although side effects are uncommon.
- Serious: Stop taking it and get prompt medical help for marked muscle weakness, unusual drowsiness, or a slow or irregular heartbeat, which can signal mineral buildup. Call 911 for throat swelling or trouble breathing.
Who should not take it?
Do not take it if you are allergic to an ingredient. Ask a doctor first if you have kidney disease or follow a diet that restricts magnesium; children under 12 also need medical guidance. Have a pharmacist check your prescriptions and supplements, including iron, multivitamins, and aspirin. Discuss pregnancy or breastfeeding before use. The MAG-AL label has no specific alcohol prohibition, but alcohol can trigger heartburn.
When is it an emergency?
For an overdose, call Poison Control at 1-800-222-1222 immediately, even without symptoms. Excess magnesium can cause severe weakness, drowsiness, low blood pressure, or a slow heartbeat. Call 911 for collapse, breathing trouble, inability to wake up, or swelling of your tongue or throat. Chest pressure with sweating or shortness of breath also needs 911; do not assume it is heartburn. Vomiting blood or passing black, tarry stools needs emergency evaluation.
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Common questions
What is the maximum daily dose?
For MAG-AL liquid with 200 mg of each ingredient per 5 mL, do not exceed 80 mL in 24 hours. Its labeled dose is 10 to 20 mL four times daily for ages 12 and older. Other strengths and tablets have different directions. Do not transfer this limit to another product.
Can I drink alcohol with it?
The MAG-AL label does not list a specific alcohol restriction. Alcohol can worsen your heartburn. Avoid it if it triggers symptoms, and do not take extra antacid to compensate.
Can I take it during pregnancy or breastfeeding?
Discuss use with your clinician or pharmacist first. Tell them your exact product and how often you need it. Pregnancy or breastfeeding does not justify exceeding the label dose.
Should I take it with food?
The MAG-AL liquid label does not specify taking it with meals. Follow any meal timing your clinician gives you. Shake liquid before measuring, and chew tablets thoroughly before swallowing.
What are signs of an overdose?
Possible signs include severe weakness, unusual sleepiness, and a slow or irregular heartbeat. Kidney disease increases the risk of magnesium buildup. Call Poison Control at 1-800-222-1222 immediately for an overdose. Call 911 for collapse or breathing trouble.
Can I take it with my other medicines?
Antacids can change how other medicines are absorbed. Ask a pharmacist to check every prescription and supplement you take. Iron, multivitamins, and aspirin deserve review. Some medicines need more separation than others, so get a specific schedule.