Pepto-Bismol(®) is a popular over-the-counter medicine containing the active ingredient bismuth subsalicylate. First created as a remedy for babies with diarrhea, it has a very distinct pink color. It is sometimes used by vets to treat dogs with diarrhea or Helicobacter infections, but should be kept well away from any cats in your home as they tend to be particularly sensitive to the drug. Though some dogs are also sensitive to the medicine, it is less common and the reaction tends to be milder than in cats.

Pepto-Bismol is available over-the-counter, but it’s still important that you check with your vet before giving it to your dog. This is because, like aspirin, it can increase blood serum levels of salicylate (30 mL of Pepto-Bismol is roughly equal to one 325 mg aspirin tablet) which leads to thinning of the blood and digestive tract irritation. For this reason, it’s recommended that you do not give your dog aspirin or any medicines which can thin the blood during treatment with Pepto-Bismol.

Safer Diarrhea Remedy for Dogs:

For a safer way to treat your dog’s diarrhea, this probiotic can provide quick and easy relief from symptoms without the potential risks of pepto-bismol.

Recommended Dosage

Note: The following dosages are often used when treating dogs with the original 1.75% Pepto-Bismol liquid (17.5 mg of bismuth subsalicylate per milliliter). Always seek approval from your vet before use.

To treat acute diarrhea, 0.5 mL/lb (1 US teaspoon for every 10 pounds your dog weighs) can be given every 4 to 6 hours for 5 days. The dosage can be higher depending on how severe the symptoms are and other contributing factors, with a maximum recommended dose of 0.9 mL/lb to be given every 6 to 8 hours. Shake the bottle well before use.

A dosage of 0.5 mL/lb is shown on the chart below:

Bismuth subsalicylate dosage chart for canine use
Dog’s Weight in Pounds: Dosage in mL:

When used as a coating agent during the treatment of uremic gastritis, 0.9 mL/lb is typically given three to four times daily. When treating Helicobacter gastritis with triple therapy, the following combination is recommended:

1. Metronidazole – 7 mg/lb every 8 hours.
2. Amoxicillin – 5 mg/lb every 8 hours.
3. Pepto-Bismol – 0.1 mg/lb every 4 to 6 hours.

Treatment with this protocol will last for approximately 21 days.

If your dog retches at the taste, cooling it in the refrigerator helps to make it more palatable.

Warning: The “Max Strength” formula contains double the amount of active ingredient per milliliter. If you are using the Max Strength formula, cut the above recommended dosages in half to avoid overdose.


A box of bismuth subsalicylate tabletsIf you are using Pepto-Bismol in tablet form, the equivalent dosage for treating acute diarrhea is 8.75 mg/lb every 4 to 6 hours for 5 days.

Treatment beyond 5 days is not recommended due to the increasing risk of negative effects. Instead, if symptoms persist beyond 5 days contact the vet. Diarrhea which persists despite treatment could be a sign of another underlying problem, and can also lead to severe dehydration and electrolyte imbalances which will need to be monitored.

Example Dosage: When treating a 30 pound dog with acute diarrhea a dosage of 15 mL four to six times per day may be used.


How Safe Is It?

It’s usually safe to use Pepto-Bismol in moderate amounts, though large doses or treatment over long periods of time can increase the risk of unwanted effects. Aside from this, it’s important that you see a vet to determine the cause of your dog’s diarrhea, as diarrhea can sometimes be a symptom of a larger problem including parasite infections, and in these cases the medicine may not be suitable.

When given with aspirin, blood serum levels of salicylate could become elevated, which could lead to salicylate poisoning. The effects of salicylate poisoning are serious and can include coma, breathing difficulties, tremors, seizures and internal bleeding. In the most severe cases of poisoning, death can occur.

Pregnancy/Nursing: It is recommended that owners avoid giving the medicine to pregnant or nursing pets.

Safety Guidelines

For safety reasons, tell your vet about the following before beginning treatment:

  • Tell your vet about any medication your dog is taking (particularly anticoagulants)
  • Tell the vet about medical conditions your dog suffers with (particularly ulcers or bleeding disorders)
  • Tell the vet about any negative reactions your dog has had to aspirin or to other products containing either bismuth or salicylate
  • Provide your dog with plenty of water and electrolytes to replenish what is being lost through elimination
  • If symptoms persist after 5 days of treatment, contact the vet for advice on how to proceed

Keep an eye on the color of your dog’s stools during treatment. Stools may become tinted green or gray during treatment, which is a common effect of the drug, but if it becomes tar-like (a sign of bleeding) you should contact the vet immediately.

Unless directed by a vet, avoid use alongside aspirin due to the risk of toxicity and avoid use with any other medication with blood-thinning properties (e.g. warfarin). Careful monitoring is recommended in cases where internal bleeding is likely or when other salicylate drugs are being used at the same time.

In terms of drug interactions, the medicine can interfere with the absorption of other medicines including tetracycline (if given orally).

What Is It Used For?

Bismuth subsalicylate is used to treat:

  • Diarrhea
  • Helicobacter gastritis

It is also occasionally used as a coating agent when treating uremic gastritis.

Side Effects

Despite being available over-the-counter, Pepto-Bismol can cause a number of side effects including:
More Common

  • Changes in the color of stools
  • Constipation


  • Bleeding
  • Salicylate poisoning

While gray or green tinted stools are common, tarry black stools indicates internal bleeding and warrant a call to the vet right away.


Overdoses can be dangerous due to the salicylate component of the medicine. If you suspect an overdose seek emergency veterinary attention or call the ASPCA poison control hotline on (888) 426-4435.


Dr. J. Bartges
Plumb’s Veterinary Drug Handbook (sixth edition)