Hesperian Health Guides

For Acid Indigestion, Heartburn, and Stomach Ulcers

Belly Pain, Diarrhea, and Worms: Medicines

First try treating heartburn and stomach upset with simple antacids. If they keep coming back, you will need stronger antacid medicines. If the stomach pain is caused by an ulcer, you will probably need to give a combination of antacid medicines and antibiotics to really cure the problem.


Antacids cost little and offer short-term relief from stomach pain and heartburn. None of them works for long, but for occasional problems they can help. They are sold under many different brand names, come as liquids or chewable tablets, and are made of aluminum hydroxide, magnesium hydroxide, calcium carbonate, or bismuth.

Aluminum hydroxide, magnesium hydroxide, milk of magnesia, cream of magnesia

These antacids can be used occasionally for acid indigestion or heartburn, or as a regular part of treatment of a stomach (peptic) ulcer.


These medicines interfere with tetracycline and a number of other medicines. If you are using another medicine, take it 2 hours before or after these antacids.

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Antacids with magnesium sometimes cause diarrhea, and those with aluminum may cause constipation.

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Take an antacid when you have pain, often about an hour after meals. Or take before bedtime to prevent problems when you lie down. Chew 1 or 2 tablets, or drink 10 ml (about 2 teaspoons) syrup. It is OK to use these 4 or 5 times a day, but if you have to take this much for several days in a row, you probably need a different treatment.

Calcium carbonate

Calcium carbonate is effective for occasional acid indigestion or heartburn. Chew one 850 mg tablet or two 350 mg tablets when symptoms occur. If necessary, take another dose in 2 hours.

Sodium bicarbonate, bicarbonate of soda, baking soda

Sodium bicarbonate should be used only occasionally for stomach upset with heartburn or acid indigestion. Do not treat chronic indigestion or ulcers with it. Although it helps at first, sodium bicarbonate causes the stomach to produce more acid, which soon makes things worse. As an occasional antacid, mix ½ teaspoon of sodium bicarbonate with water and drink it.

Alka-Seltzer is a combination of sodium bicarbonate and aspirin. If you have an ulcer, the aspirin in it will make the ulcer worse.


Persons with heart disease or with swelling of the feet or face should not use sodium bicarbonate or other products that contain sodium.


Bismuth usually comes as a pink liquid. It is used for heartburn, stomach ache, diarrhea, or gas (painful, bloated stomach and farting). It can be used in combination with other medicines to treat ulcer.

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Sometimes this medicine turns the tongue or feces black. This is harmless and goes away when you stop taking the medicine.


Do not give to children with fevers. Like aspirin, it may cause health problems in children with infections caused by viruses.

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Do not give within 2 hours of tetracyclines. It will stop them from working well.

Give 2 tablets or 30 ml of liquid, once an hour as needed. Do not give more than 16 tablets or 240 ml in 24 hours.

Stronger acid-reducing medicines

New medicines for heartburn and ulcer work better than the old antacids, but they can be expensive. There are two kinds of new antacids, called Histamine 2 Receptor Antagonists (H2 Blockers) and Proton Pump Inhibitors (PPIs). Of the two groups, PPIs work best but are more expensive. Medicines within each group usually work equally well, so choose the H2 Blocker or PPI that is least expensive.


Omeprazole is a PPI. Like other PPIs, it can calm pain and help an ulcer heal. To treat an ulcer, try using omeprazole alone for 8 weeks. If the ulcer and pain come back, try using omeprazole again with a combination of antibiotics to cure the problem.

If you do not have good results with omeprazole, try a different PPI instead.

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Give 20 to 40 mg, once a day.
Start with 20 mg, and if pain does not improve, increase to 40 mg.

If the ulcer or pain comes back within 6 months after taking omeprazole, also use antibiotics to cure the ulcer.


Ranitidine is an H2 blocker. Like other H2 blockers, it can calm pain and help an ulcer heal. But if the pain comes back within 6 months of taking ranitidine, also use antibiotics to cure the ulcer. See "To cure an ulcer" below.

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Give 150 mg twice a day, or 300 mg with the evening meal, for 4 to 8 weeks.

To cure an ulcer

Give a combination of antacid medicines and antibiotics. There are many combinations that will work. Most include one PPI and two antibiotics. Often bismuth is added as well. If you do not have a PPI, an H2 blocker may work instead.

Here is one combination:
Omeprazole 40 mg, (or another PPI) once a day for 1 or 2 weeks
Metronidazole 500 mg, twice a day for 1 or 2 weeks
Amoxicillin 500 mg, 3 times a day for 1 or 2 weeks.

OR, this is another option:

Omeprazole 40 mg, (or another PPI) once a day for 1 week
Metronidazole 250 mg, 4 times a day for 1 week
Tetracycline 500 mg, 4 times a day for 1 week
Bismuth 525 mg, 4 times a day for 1 week
Do not take tetracycline and bismuth at the same time. Wait 2 to 3 hours after taking one, and then take the other.

This page was updated:05 Jan 2024