What Does Pepto Bismol Do

Drink plenty of liquids while you are taking this medicine.

What to know about Pepto Bismol

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Pepto Bismol is a common over-the-counter (OTC) drug that may help control occasional symptoms of simple digestive issues, such as indigestion, heartburn, and diarrhea.

Pepto Bismol is an antacid. It is available in a variety of forms, including capsules and liquids, and comes in a range of strengths. Some people may experience specific side effects, such as very dark or black stool, after taking Pepto Bismol. However, these side effects are generally temporary and harmless.

The drug may also interact with other medications, such as anticoagulants, or blood thinners. A person should only use Pepto Bismol or similar products for a short period to treat occasional symptoms. Anyone dealing with chronic digestive symptoms should speak with their doctor.

This article provides an overview of Pepto Bismol, including its uses, risks, and instructions.

a woman taking Pepto Bismol on a spoon

Bismuth subsalicylate is the main active ingredient in Pepto Bismol. It is an antacid medication that also works to lower inflammation in the digestive system.

As a study published in the journal Clinical and Experimental Gastroenterology notes, bismuth has antidiarrheal, antibacterial, and anti-inflammatory properties in the body.

These combined efforts may help with digestive symptoms such as:

In some cases, and always under a doctor’s guidance, people may use Pepto Bismol and other drugs to help treat infections caused by the bacteria H. pylori and symptoms that arise from them. Sometimes, a doctor may recommend it to treat symptoms of chronic digestive disorders.

Some people also find the antibacterial effects of Pepto Bismol useful when traveling to unfamiliar areas where the local bacteria may infect their digestive system and cause traveler’s diarrhea.

No one should self-diagnose an underlying issue and use Pepto Bismol to treat it. Anyone whose symptoms get worse or last more than 2 days should contact a doctor for a full diagnosis.

Pepto Bismol comes in various forms, including:

  • oral liquid
  • oral liquid capsules
  • oral tablets
  • chewable tablets

Each option contains various strengths and dosages of bismuth subsalicylate designed for specific symptoms and how fast a person needs relief.

A chewable tablet for symptoms in children is also available. However, the active ingredient in this product is calcium carbonate, not bismuth subsalicylate.

Share on Pinterest Pepto Bismol is available as chewable tablets.

Anyone taking Pepto Bismol to treat occasional digestive symptoms should follow the instructions on the label.

The original liquid Pepto Bismol includes a 30 milliliter (ml) cup, which is one dose, delivering 525 milligrams (mg) of bismuth subsalicylate. The Pepto Bismol website recommends taking:

  • One 30 ml dose every 30 minutes as needed for stomach upset, nausea, heartburn, and indigestion
  • One 30 ml dose every 30 minutes or two doses every hour for diarrhea or traveler’s diarrhea

It also warns not to take more than eight doses in 24 hours.

When using the original chewable tablets, one dose is two tablets. The recommended dose is:

  • Two tablets every 30 minutes or four tablets every hour for diarrhea
  • Two tablets every 30 minutes for stomach upset, nausea, heartburn, and indigestion

Similarly, do not take more than eight doses (16 tablets) in 24 hours.

Pepto Bismol Extra Strength is a more concentrated liquid but delivers the same amount of active ingredient per recommended dose — 525 mg of bismuth subsalicylate in 15 ml of liquid.

For children under the age of 12, use children’s versions of similar medications or talk to a doctor before using Pepto Bismol.

Do not take more Pepto Bismol than directed, even if symptoms do not clear up.

Anyone using Pepto Bismol or similar drugs to treat more serious issues, such as infection, must follow the specific instructions from their doctor.

Side effects from using bismuth subsalicylate are not common. The most common side effects are a very dark or black stool, and darkening on the tongue. This is a reaction to the bismuth and is temporary. The discoloration should go away when the person stops taking the product.

Most people do not experience any serious side effects. However, people who are allergic to salicylate, which is a chemical found in aspirin, may experience more severe side effects. Anyone who is allergic to these ingredients can talk to their doctor about alternatives to using Pepto Bismol.

In rare cases, a person may experience ringing in their ears or hearing loss. If this occurs, the person should stop taking the product immediately and contact a doctor.

An extreme reaction might result in internal bleeding in the stomach or intestines. Anyone experiencing symptoms such as severe cramps, bloody or dark, sticky stool, or vomit that looks similar to coffee grounds, should stop taking the drug and contact a doctor immediately.

Children or teens who are recovering from chickenpox or the flu should not take Pepto Bismol. Taking Pepto Bismol in these situations could cause Reye’s syndrome. Symptoms of Reye’s syndrome include changes in behavior, nausea, vomiting, and seizures. This is a rare reaction, but it can be a medical emergency.

There is little evidence that Pepto Bismol causes harmful side effects during pregnancy, though there is little research to say that it is safe either.

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Similarly, it is unclear if bismuth subsalicylate passes through the breastmilk.

Pregnant or breastfeeding women should always consult a doctor before using Pepto Bismol or any medicine that contains bismuth subsalicylate.


Generic name: bismuth subsalicylate [ BIZ-muth-sub-sa-LISS-i-late ]
Brand names: Bismarex, Bismatrol, Bismatrol Maximum Strength, Kaopectate, Kola-Pectin DS, . show all 10 brands Peptic Relief, Pepto-Bismol, Percy Medicine, Pink Bismuth, Soothe Caplets
Drug class: Antidiarrheals

Medically reviewed by Melisa Puckey, BPharm. Last updated on Jul 21, 2022.

What is Pepto-Bismol?

Pepto-Bismol works as an antacid to reduce excess stomach acid and so eases discomfort. It also works to protect the stomach and lower part of your food pipe (esophagus) from stomach acid.

Pepto-Bismol can be taken as a tablet or liquid, depending on which one you prefer.


You should not use Pepto-Bismol if you have bleeding problems, blood in your stools, or if you are allergic to aspirin or other salicylates.

You should not use Pepto-Bismol for a stomach ulcer unless your ulcer is caused by H. pylori and your doctor has prescribed Pepto-Bismol as part of modified bismuth-containing quadruple therapy (mBCQT).

Do not give this medicine to a child or teenager with a fever, flu symptoms, or chickenpox.

Related/similar drugs

Before taking this medicine

You should not use Pepto-Bismol if you are allergic to bismuth subsalicylate, or if you have:

  • black or bloody stools;
  • a stomach ulcer (unless your doctor has prescribed Pepto-Bismol as part of modified bismuth-containing quadruple therapy);
  • bleeding problems; or
  • if you are allergic to salicylates such as aspirin, Doan’s Extra Strength, Salflex, Tricosal, and others.

Do not give this medicine to a child or teenager with a fever, flu symptoms, or chickenpox. Salicylates can cause Reye’s syndrome, a serious and sometimes fatal condition in children.

Ask a doctor or pharmacist if this medicine is safe to use if you have:

  • mucus in your stools; or
  • if you currently have a fever.

Ask a doctor before using this medicine if you are pregnant or breastfeeding.

Do not give this medicine to a child younger than 12 years old without medical advice.

How should I take Pepto-Bismol?

Take this medicine exactly as directed on the label, or as prescribed by your doctor.

Shake the oral suspension (liquid) before you measure a dose. Use the dosing syringe provided, or use a medicine dose-measuring device (not a kitchen spoon).

You must chew the chewable tablet before you swallow it.

Drink plenty of liquids while you are taking this medicine.

Do not take more than 8 doses in one day (24 hours).

Call your doctor if you still have diarrhea after 2 days of using this medicine.

This medicine can affect the results of certain medical tests. Tell any doctor who treats you that you are using bismuth subsalicylate.

Store at room temperature away from moisture and heat. Do not freeze.

What happens if I miss a dose?

Since bismuth subsalicylate is used when needed, you may not be on a dosing schedule. Skip any missed dose if it’s almost time for your next dose. Do not use two doses at one time.

Do not take more than 8 doses per day.

What happens if I overdose?

Seek emergency medical attention or call the Poison Help line at 1-800-222-1222.

Overdose symptoms may include weakness, depression, anxiety, feeling irritable, problems with balance or coordination, confusion, tremors, or jerky muscle movements.

What should I avoid while taking Pepto-Bismol?

Ask a doctor or pharmacist before taking other antacids or diarrhea medicine, or taking medicine that may contain a salicylate (such as aspirin, salsalate, magnesium salicylate, choline salicylate, diflunisal, Ecotrin, Tricosal, Trilisate, and others).

Pepto-Bismol side effects

Get emergency medical help if you have signs of an allergic reaction: hives; difficulty breathing; swelling of your face, lips, tongue, or throat.

Stop taking this medicine and call your doctor at once if you have:

  • changes in behavior with nausea and vomiting;
  • hearing loss or ringing in your ears;
  • diarrhea lasting longer than 2 days; or
  • worsened stomach symptoms.

Bismuth subsalicylate can cause you to have a black or darkened tongue. This is a harmless side effect.

Common side effects include:

  • constipation; or
  • dark colored stools.

This is not a complete list of side effects and others may occur. Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088.

What other drugs will affect Pepto-Bismol?

Ask a doctor or pharmacist before using bismuth subsalicylate with any other medications, especially:

  • arthritis medicine;
  • gout medicine;
  • insulin or oral diabetes medications; or
  • a blood thinner–warfarin, Coumadin, Jantoven.

This list is not complete. Other drugs may affect Pepto-Bismol, including prescription and over-the-counter medicines, vitamins, and herbal products. Not all possible drug interactions are listed here.

Where can I get more information?

Remember, keep this and all other medicines out of the reach of children, never share your medicines with others, and use this medication only for the indication prescribed.

Frequently asked questions

  • Pepto-Bismol – How long will your stool be dark for?
  • How to stop diarrhea – any medicine or remedy suggestions?
  • Is using expired Pepto-Bismol a hazard or health risk?
  • My stool has changed color. What does it mean?

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What Does Pepto-Bismol Do? Find Relief and Avoid Side Effects

Barbara Bolen, PhD, is a licensed clinical psychologist and health coach. She has written multiple books focused on living with irritable bowel syndrome.

Updated on September 12, 2022

Robert Burakoff, MD, MPH, is board-certified in gastroentrology. He is the vice chair for ambulatory services for the department of medicine at Weill Cornell Medical College in New York, where he is also a professor. He was the founding editor and co-editor in chief of Inflammatory Bowel Diseases.

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Table of Contents
Table of Contents

Pepto-Bismol (bismuth subsalicylate) is an over-the-counter treatment for diarrhea, upset stomach, and nausea. Sometimes referred to as “the pink stuff,” Pepto-Bismol is safe and effective for short-term use.

Side effects of Pepto-Bismol are generally mild and can include a black tongue, black stool, and constipation. More serious side effects can occur but are rare. This article discusses Pepto-Bismol, how it works, and potential side effects.

Safety Tips for Taking Pepto-Bismol


Pepto-Bismol is primarily used for the short-term treatment of the following digestive symptoms in adults and children aged 12 and older:

  • Diarrhea
  • Nausea
  • Stomach upset
  • Indigestion
  • Heartburn
  • Excessive intestinal gas
  • Excessive burping
  • A feeling of fullness caused by eating too much
  • Discomfort from drinking too much alcohol

Interestingly, researchers have found that when Pepto-Bismol is combined with antibiotics, it can be quite effective in treating Helicobacter pylori, an infection that has been linked to peptic ulcers and gastritis.

How Pepto-Bismol Works

The scientific name for the active ingredient in Pepto-Bismol is bismuth subsalicylate. Bismuth is a mineral that has antibacterial, antacid, and antidiarrheal effects. Subsalicylate is a medication in the same class as aspirin.

The active ingredients of Pepto-Bismol are thought to have the following actions within the body:

  • Increasing the amount of fluid that is absorbed in the intestines, therefore firming up stool
  • Reducing inflammation
  • Calming intestinal spasms
  • Reducing the population of disease-causing bacteria and/or viruses
  • Reducing excess levels of stomach acid

Side Effects

Pepto-Bismol is considered quite safe for short-term use by adults and children aged 12 or over.

Common Side Effects

When used properly, Pepto-Bismol has a few side effects:

  • Blackening of the tongue
  • Dark or black stool
  • Constipation

These side effects are temporary and generally harmless.

Serious Side Effects

Serious side effects of Pepto-Bismol are rare but not unheard of.

Adults over the age of 65: The side effect of constipation may lead to a bowel blockage, a serious condition.

Children and teens: Pepto-Bismol is in the aspirin family. Aspirin use in children and teenagers is associated with a risk of Reye’s syndrome, a potentially life-threatening illness. This risk is particularly high for those who have chickenpox, influenza (the flu), or any other type of viral infection.​

Pepto Kids, a formulation made for children, does not contain bismuth subsalicylate and is safe for children. Pepto Kids is designed to treat heartburn and upset stomach in children.

When To Call Your Healthcare Provider

Contact your healthcare provider immediately and stop taking Pepto-Bismol if you experience:

  • Ringing in the ears
  • Diarrhea that lasts for more than two days
  • Severe vomiting
  • High fever
  • Any signs of an allergic reaction

If you think you have taken an overdose or are experiencing any severe symptoms, seek immediate attention by calling an ambulance.

Before Taking

Pepto-Bismol is only recommended for use for a two-day period. That, therefore, makes it a poor choice as a treatment for people who experience chronic diarrhea, common in those with IBS. It also makes it a poor choice for people who experience chronic heartburn or acid reflux from gastroesophageal reflux disease (GERD).

Before taking Pepto-Bismol, it is essential that you clear it with your healthcare provider, as the medication may interact with other medications that you are taking, particularly some medications for diabetes or gout, blood thinners, and certain antibiotics.

Precautions and Contraindications

Pepto-Bismol should not be taken by anyone who:

  • Is younger than 12 years of age
  • Has the flu
  • Has a fever and signs of blood in the stool
  • Has chickenpox or has received the chickenpox vaccination within the past six weeks
  • Is pregnant
  • Is breastfeeding
  • Is allergic to aspirin or nonsteroidal anti-inflammatory drugs (NSAIDs)


Pepto-Bismol is an oral medication that comes in liquid, tablet, or chewable form. Follow the directions and dosing recommendations on the product packaging carefully.

You do not need to take the medication with food. Do not take Pepto-Bismol for more than two days. Be sure to drink plenty of water while taking Pepto-Bismol to replace fluid lost from diarrhea episodes.

A Word From Verywell

Although it may be tempting to take Pepto-Bismol to address irritable bowel symptoms, remember that it is only recommended for a maximum of two days. Thus, it is best only for short-term symptoms, and long-term use may enhance side effects. When you’re experiencing chronic symptoms, work with your healthcare provider to find a better solution.

Frequently Asked Questions

What are the side effects of Pepto-Bismol?

The most common side effect of Pepto-Bismol is a black tongue or black stools. Both are harmless. Pepto-Bismol contains a non-toxic metal called bismuth that, when mixed with sulfur (a naturally occurring mineral in the body), forms a black substance called bismuth sulfide.

Can Pepto-Bismol cause severe side effects?

  • Severe vomiting
  • Blood in the stool (usually mild)
  • Coffee ground-like vomit (a sign of gastric bleeding)
  • Tinnitus (ringing or buzzing in the ears)

Who should not take Pepto-Bismol?

  • Aspirin allergy
  • Gastric ulcer
  • Hematochezia (bloody stools)
  • Hemophilia
  • Flu-like symptoms (for children and teens only due to the risk of Reye’s syndrome)

Also, children under age 12 should not take regular Pepto-Bismol; children under 2 shouldn’t be given Pepto Kids.

Is Pepto-Bismol safe during pregnancy?

Pepto-Bismol contains bismuth subsalicylate, a drug that is generally avoided during the third trimester as it increases the risk of uterine bleeding. There remains considerable debate about the actual risk, but it may be best to avoid Pepto-Bismol just to be safe.

What drugs interact with Pepto-Bismol?

  • Arthritis or gout medications
  • Blood thinners like warfarin
  • Daily aspirin
  • Diabetes medications
  • Tetracycline antibiotics

What are the alternatives to Pepto-Bismol?

  • Heartburn can be relieved with antacids, H2 blockers, or proton pump inhibitors (PPIs).
  • Indigestion can be relieved with Alka-Seltzer (sodium bicarbonate) or Mylanta (simethicone)
  • Constipation can be treated with stool softeners and osmotic, stimulant, or bulk-forming laxatives
  • Diarrhea can be treated with Imodium (loperamide)
  • Nausea may be treated with Dramamine (dimenhydrinate) or Bonine (meclizine).

How long does it take Pepto-Bismol to work?

Pepto-Bismol generally starts to work within 30 minutes to an hour. If you aren’t feeling relief after an hour, you can take a second dose.

Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.

  1. U.S. National Library of Medicine. Label: Pepto-Bismol—bismuth subsalicylate kit.
  2. Graham DY, Lee SY. How to effectively use bismuth quadruple therapy: The good, the bad, and the ugly. Gastroenterol Clin North Am. 2015;44(3):537-63. doi:10.1016/j.gtc.2015.05.003
  3. Procter & Gamble. Pepto Bismol Original Liquid [package labeling].
  4. Budisak P, Abbas M. Bismuth subsalicylate. In: StatPearls [Internet].
  5. Servery J, Chang J. Over-the-counter medications in pregnancy. Am Fam Physician. 2014 Oct 15;90(8):548-55.
  6. MedlinePlus. Bismuth subsalicylate.

By Barbara Bolen, PhD
Barbara Bolen, PhD, is a licensed clinical psychologist and health coach. She has written multiple books focused on living with irritable bowel syndrome.

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