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Bismuth subsalicylate is used to treat diarrhea and symptoms of an upset stomach, such as heartburn, indigestion, nausea, gas, burping, or fullness. Common side effects may include nausea, a black tongue, or black poop. Serious side effects are rare but may include ringing in the ears and a condition called Reye’s syndrome (in children and teens). Bismuth subsalicylate is taken by mouth and is available in several forms, including a tablet, capsule, chewable tablet, and liquid. 

Uses

What is bismuth subsalicylate used for?

Bismuth subsalicylate is commonly used to treat the following conditions.

  • Diarrhea, including traveler’s diarrhea
  • Upset stomach due to overindulgence of food and drink, including heartburn, indigestion, nausea, gas, burping, or fullness

Bismuth subsalicylate may also be used for other conditions as determined by your health care provider.

How does bismuth subsalicylate work (mechanism of action)?

Bismuth subsalicylate may work by coating and protecting the inside of your stomach. It may also help reduce inflammation. For diarrhea, bismuth subsalicylate can help lessen the amount of fluids going into your intestines, making your poop less watery. The medicine also has some antibacterial effects, which may help kill certain bacteria that cause diarrhea. 

How is bismuth subsalicylate supplied (dosage forms)?

Brands and other names

  • K-Pek
  • Kaopectate
  • Kao-Tin
  • Maalox
  • Pepto-Bismol
  • Pink Bismuth

Example dosage forms and strengths

  • 262 mg chewable tablets
  • 262 mg oral capsules
  • 262 mg/15 mL, 525 mg/15 mL, 525 mg/30 mL, 1050 mg/30 mL oral suspension
  • 262 mg oral tablets

How should I store bismuth subsalicylate?

Bismuth subsalicylate should be stored at room temperature, between 68 F and 77 F (20 C and 25 C). It can be exposed to temperatures between 59 F and 86 F (15 C and 30 C) for shorter periods of time, such as when transporting it. Store in a cool, dry place. Avoid excessive heat over 104 F (40 C), and protect from freezing. 

Side Effects

What are the most common side effects of bismuth subsalicylate?

The most common side effects of bismuth subsalicylate are listed below. Tell your health care provider if you have any of these side effects that bother you.

  • Nausea
  • Black tongue and black poop

There may be other side effects of bismuth subsalicylate that are not listed here. Contact your health care provider if you think you are having a side effect of a medicine. In the U.S., you can report side effects to the FDA at www.fda.gov/medwatch or by calling 800-FDA-1088 (800-332-1088). In Canada, you can report side effects to Health Canada at www.health.gc.ca/medeffect or by calling 866-234-2345.

What are the serious side effects of bismuth subsalicylate?

While less common, the most serious side effects of bismuth subsalicylate are described below, along with what to do if they happen.

Severe Allergic Reactions. Bismuth subsalicylate may cause allergic reactions, which can be serious. Stop taking bismuth subsalicylate and get help right away if you have any of the following symptoms of a serious allergic reaction.

  • Breathing problems or wheezing
  • Racing heart
  • Fever or general ill feeling
  • Swollen lymph nodes
  • Swelling of the face, lips, mouth, tongue, or throat
  • Trouble swallowing or throat tightness
  • Itching, skin rash, or pale red bumps on the skin called hives
  • Nausea or vomiting
  • Dizziness, feeling lightheaded, or fainting
  • Stomach cramps
  • Joint pain

Reye’s Syndrome. Reye’s syndrome is a rare but serious condition that can cause swelling in the brain and liver. Bismuth subsalicylate should not be taken by children and teens who have or have recently had flu-like symptoms or chickenpox, as it may increase the risk of Reye’s syndrome. Stop taking bismuth subsalicylate and call your health care provider right away if you have changes in behavior along with nausea and vomiting, as these may be early signs of Reye’s syndrome. 

Ear Problems. Stop taking bismuth subsalicylate and call your health care provider if you have ringing in your ears or hearing loss. 

Warnings & Precautions

Who should not use bismuth subsalicylate?

Allergies to Ingredients. People who are allergic to any of the following should not take bismuth subsalicylate.

  • Bismuth subsalicylate
  • Salicylates, including aspirin
  • Any of the ingredients in the specific product

Your pharmacist can tell you all of the ingredients in the specific bismuth subsalicylate products they stock.

Chickenpox or Flu-Like Symptoms. Children and teens who have or recently had chickenpox, the flu, or flu-like symptoms should not take bismuth subsalicylate. Doing so may increase the risk of a rare but serious condition called Reye’s syndrome. See the Side Effects section for more details.

Bleeding Problems. Do not take bismuth subsalicylate if you have bleeding problems, including stomach bleeding or black or bloody poop. 

Ulcers. Do not take bismuth subsalicylate if you have an ulcer without talking to your health care provider first. 

Drug Interactions. Bismuth subsalicylate should not be taken while you are using certain other medicines. Before taking bismuth subsalicylate, tell your health care provider about any prescription or over-the-counter (OTC) medicines, vitamins/minerals, herbal products, and other supplements you are using. See the Interactions section for more details.

What should I know about bismuth subsalicylate before using it?

Read and follow the instructions that come with the medicine. There are several forms of bismuth subsalicylate available, which may be taken in different ways. 

Do not take more bismuth subsalicylate than is recommended. Ask your pharmacist or other health care provider if you are not sure how much bismuth subsalicylate to take or how often to take it. 

Keep bismuth subsalicylate out of the reach of children and pets.

If you are taking bismuth subsalicylate liquid, use the dosing cup that comes with the product to measure your dose. A household spoon is not an accurate measuring device and may cause you to take the wrong dose. Shake the bismuth subsalicylate liquid well before taking each dose. Talk to your pharmacist if you have any questions. 

Check the label for the bismuth subsalicylate product you have. Some bismuth subsalicylate tablets and capsules should not be cut, crushed, or chewed and should be swallowed whole. Some bismuth subsalicylate tablets are chewable and should be chewed well before swallowing. Ask your pharmacist or other health care provider if you are not sure.

If your symptoms, including diarrhea, get worse or last more than two days, stop taking bismuth subsalicylate and call your health care provider. 

If you are taking bismuth subsalicylate for diarrhea, drink plenty of clear fluids to help prevent dehydration. 

Bismuth subsalicylate may affect the results of X-rays or certain lab tests. Tell all of your health care providers that you are taking this medicine before any procedures or blood tests.

What should I tell my health care provider before using bismuth subsalicylate?

Tell your health care provider about all of your health conditions and any prescription or over-the-counter (OTC) medicines, vitamins/minerals, herbal products, and other supplements you are using. This will help them know if bismuth subsalicylate is right for you.

In particular, make sure that you discuss any of the following.

Current and Past Health Conditions. Tell your health care provider if you have any of the following.

Low-Salt Diet. Tell your health care provider if you are following a low-salt (sodium) diet. Some forms of bismuth subsalicylate contain sodium.

Pregnancy. Do not take bismuth subsalicylate at 20 weeks or later in pregnancy without talking to your health care provider. Taking bismuth subsalicylate during this time may cause harm to a fetus and complications during delivery. Tell your health care provider if you are pregnant or plan to become pregnant. Your health care provider will let you know if you should take bismuth subsalicylate while you are pregnant or trying to get pregnant.

Breastfeeding. It is not known if bismuth subsalicylate passes into breast milk. Tell your health care provider if you are breastfeeding or plan to breastfeed. Your health care provider will let you know if you should take bismuth subsalicylate while breastfeeding.

Interactions

Does bismuth subsalicylate interact with foods or drinks?

There are no known interactions between bismuth subsalicylate and foods or drinks.

It is unknown if drinking alcohol will affect bismuth subsalicylate, but both bismuth subsalicylate and alcohol may increase your risk of bleeding. If you have diarrhea, drinking alcohol may make diarrhea worse or increase your risk of dehydration. It is best to limit the amount of alcohol you drink while taking bismuth subsalicylate.

Does bismuth subsalicylate interact with other medicines (drug interactions)?

Always tell your health care provider about any prescription or over-the-counter (OTC) medicines, vitamins/minerals, herbal products, and other supplements you are using.

In particular, make sure that you discuss if you are using any of the following before taking bismuth subsalicylate.

  • A salicylate, such as diflunisal or salsalate, which is a medicine used for arthritis
  • A nonsteroidal anti-inflammatory drug (NSAID), such as aspirin, ibuprofen, naproxen, and others, which is in many prescription and OTC products for pain, swelling, and fever 
  • Any other medicine for arthritis
  • A blood thinner, which is a medicine used to treat or prevent blood clots
  • A medicine for diabetes
  • A medicine for gout

This may not be a complete list of medicines that can interact with bismuth subsalicylate. Always check with your health care provider.

Does interact with other drugs you are taking?

Enter your medication into the WebMD interaction checker

Overdose/Missed Dose

What should I do if I accidentally use too much bismuth subsalicylate?

If you or someone else has used too much bismuth subsalicylate, get medical help right away, call 911, or contact a Poison Control center at 800-222-1222.

What should I do if I miss a dose of bismuth subsalicylate?

Bismuth subsalicylate is usually meant to be taken only when needed. Use it as directed on the label or as your health care provider recommends. Do not take double or extra doses.