Understanding What Is the Downside of Taking Pepto-Bismol?

October 8, 2025 •

3 min read

While considered a common household remedy, Pepto-Bismol, or bismuth subsalicylate, is not without its risks, and taking it without understanding the downsides can lead to unexpected side effects. In rare cases, especially with misuse or in susceptible individuals, the consequences can be severe, extending beyond temporary cosmetic changes.

Quick Summary

Despite its common use, Pepto-Bismol carries notable risks and side effects, including temporary black tongue and stool, and potentially serious issues like salicylate toxicity, Reye's syndrome in children, and dangerous drug interactions.

Key Points

Black Tongue and Stools: A common, but harmless side effect where bismuth combines with sulfur in the digestive system, temporarily darkening the tongue and feces.
Reye's Syndrome Risk in Children: Contains a salicylate similar to aspirin, which poses a risk of this rare but serious and potentially fatal condition in children and teens with viral illnesses; do not give to children under 12.
Salicylate Toxicity (Overdose): Excessive use can lead to overdose, causing symptoms like persistent ringing in the ears (tinnitus), hearing loss, confusion, and rapid breathing.
Dangerous Drug Interactions: Can dangerously interact with blood thinners, other salicylates (aspirin), and certain antibiotics, increasing the risk of bleeding and reducing medication effectiveness.
Neurotoxicity from Chronic Use: Very rare but serious neurological issues, including confusion and myoclonic jerks, can occur from long-term, high-dose use due to bismuth accumulation.
Masks Underlying Conditions: Using it long-term can hide a more serious gastrointestinal problem, delaying proper diagnosis and treatment.
Contraindicated for Specific Groups: Should be avoided by pregnant or breastfeeding individuals, those with bleeding disorders, stomach ulcers, or kidney disease.

Common Side Effects to Be Aware Of

Common side effects of Pepto-Bismol include temporary black discoloration of the tongue and stool, caused by the reaction of bismuth with sulfur in the digestive tract. This effect is harmless and temporary. Other potential side effects include nausea and constipation, and sometimes a bitter taste in the mouth. These usually subside after stopping the medication.

Serious Risks and Contraindications

Pepto-Bismol contains salicylate, similar to aspirin, and carries associated risks.

Reye's Syndrome in Children and Teenagers

Pepto-Bismol should not be given to children under 12 or anyone under 18 recovering from viral illnesses like the flu or chickenpox, due to the rare but life-threatening risk of Reye's syndrome.

Salicylate Toxicity (Overdose)

Overdosing can lead to salicylate toxicity, particularly in individuals with kidney disease, the elderly, or those taking other salicylate medications. Symptoms can include ringing in the ears, hearing loss, rapid breathing, confusion, dizziness, vomiting, and in severe cases, seizures and cardiac arrest.

Bismuth Neurotoxicity from Chronic Use

Rarely, long-term, excessive use can cause bismuth encephalopathy, a neurological condition resulting from bismuth buildup. Symptoms include memory loss, confusion, coordination problems, muscle twitching, and weakness. Recovery can take months after stopping the medication.

Allergic Reactions

Avoid Pepto-Bismol if allergic to aspirin or other salicylates, as it can cause severe reactions like hives or difficulty breathing.

Pre-existing Medical Conditions

Individuals with bleeding disorders, stomach ulcers (unless directed by a doctor for H. pylori), or kidney or liver disease should avoid Pepto-Bismol due to increased risks of bleeding or toxicity.

Drug Interactions and Absorption Issues

Pepto-Bismol can affect other medications.

Medications to avoid with Pepto-Bismol

Combining Pepto-Bismol with blood thinners like warfarin or anti-platelet drugs increases bleeding risk. Using it with other salicylates or NSAIDs like ibuprofen increases toxicity and bleeding risk. It can also reduce the effectiveness of certain antibiotics and interact with medications for gout and diabetes.

Long-Term Consequences of Masking Symptoms

Chronic use of Pepto-Bismol can hide serious underlying digestive issues like ulcers or IBS, delaying proper medical diagnosis and treatment. Consult a doctor if symptoms last more than 48 hours.

Pepto-Bismol vs. Alternatives: A Comparison

Here is a comparison of Pepto-Bismol with other common alternatives for treating digestive issues.


Feature	Pepto-Bismol (Bismuth Subsalicylate)	Imodium (Loperamide)	Tums (Calcium Carbonate)	Ginger
Mechanism	Coats and soothes stomach lining, has antimicrobial effects, and reduces inflammation. Contains salicylate.	Slows down the movement of the gut to reduce the frequency of diarrhea.	Neutralizes stomach acid to relieve heartburn and indigestion.	Nausea relief through natural compounds, and may aid digestion.
Diarrhea Use	Effective for diarrhea and traveler's diarrhea. Not for use with bloody stools or fever.	Specifically for diarrhea. Doesn't cause Reye's syndrome.	Not for diarrhea.	Can help with motion sickness and nausea, not specific for bacterial diarrhea.
Nausea Use	Effective for nausea and upset stomach.	Not effective for nausea.	Not a primary treatment for nausea.	Commonly used for nausea.
Drug Interactions	Significant interactions with blood thinners, salicylates, and some antibiotics.	Fewer interactions, but may interact with some medications.	Few, but can interfere with some antibiotics and thyroid medications.	Can affect blood clotting and blood sugar levels in large amounts.
Risk for Children	High risk of Reye's syndrome; contraindicated for under 12 years.	Generally safe for children over a certain age under doctor's guidance.	Contains no salicylates; safe for children over 2 (e.g., Pepto Kids).	Often safe, but consult a doctor for pediatric use.
Long-Term Use	Not recommended due to potential bismuth toxicity.	Not recommended for prolonged periods.	Generally safe for regular use for calcium supplementation, but overuse can cause other issues.	Safe for many, but consult a doctor for large quantities or health conditions.

Conclusion: Responsible Use is Key

Pepto-Bismol can be effective for occasional digestive upset, but its salicylate content poses risks. The most significant danger is Reye's syndrome in children and teenagers with viral illnesses. Adults risk salicylate toxicity, especially with other salicylate-containing medications. Chronic use carries a rare risk of bismuth neurotoxicity. Persistent symptoms may indicate a more serious condition requiring medical attention. Always read labels, be aware of drug interactions, and consult a healthcare professional if unsure. Short-term, responsible use according to guidelines is crucial to minimize risks.

For more detailed information, consult the National Institutes of Health's article on bismuth subsalicylate.

Frequently Asked Questions

The black discoloration is a temporary and harmless side effect that occurs when the bismuth in Pepto-Bismol reacts with sulfur in your digestive tract to form bismuth sulfide. It will resolve once you stop taking the medication.

No, children under 12 should not take regular Pepto-Bismol, and it's contraindicated for anyone under 18 with viral symptoms due to the risk of Reye's syndrome. There is a separate product called Pepto Kids for children over 2 that does not contain bismuth subsalicylate.

Taking too much can lead to salicylate toxicity (overdose). Symptoms can include ringing in the ears, hearing loss, rapid breathing, confusion, and anxiety. In severe cases, it can cause seizures.

You should be cautious, as it interacts with blood thinners (increasing bleeding risk) and can reduce the effectiveness of some antibiotics like tetracyclines. Always consult a doctor or pharmacist, especially if you take aspirin or other NSAIDs.

Long-term use is not recommended and can mask a more serious underlying condition. In very rare cases of chronic overuse, it can lead to bismuth neurotoxicity.

People with allergies to salicylates (like aspirin), bleeding disorders, stomach ulcers, kidney or liver disease, and those who are pregnant or breastfeeding should avoid Pepto-Bismol.

Alternatives depend on the symptom. Options include loperamide (Imodium) for diarrhea, calcium carbonate (Tums) for heartburn, and natural remedies like ginger for nausea. For children, Pepto Kids contains calcium carbonate and is a safer alternative.