How long can it take for Pepto Bismol (bismuth subsalicylate) to take effect?

Medical Advisory BoardAll articles are reviewed for accuracy by our Medical Advisory Board
Educational purpose only • Exercise caution as content is pending human review
Article Review Status
Submitted
Under Review
Approved

Last updated: April 3, 2025View editorial policy

Personalize

Help us tailor your experience

Which best describes you? Your choice helps us use language that's most understandable for you.

From the Guidelines

Pepto-Bismol should not be taken for more than 2 days (48 hours) for adults and children 12 years and older. This recommendation is based on the guidelines for adults on self-medication for the treatment of acute diarrhoea, which suggests that bismuth subsalicylate, the active ingredient in Pepto-Bismol, is less effective than loperamide, even in travellers' diarrhoea caused by E. coli 1.

Key Considerations

  • The standard adult dosing is typically 2 tablets or 30 mL (2 tablespoons) every 30-60 minutes as needed, not exceeding 8 doses in 24 hours.
  • Pepto-Bismol contains bismuth subsalicylate, which can temporarily relieve symptoms like diarrhea, upset stomach, indigestion, and nausea by reducing inflammation in the digestive tract and killing certain bacteria.
  • Extended use can lead to side effects including constipation, darkened stools or tongue, and in rare cases, more serious complications.
  • If you're taking other medications, especially blood thinners, aspirin, or certain antibiotics, check with your doctor before using Pepto-Bismol as it may interact with these medications.

Special Populations

  • For children under 12, consult a doctor before using Pepto-Bismol at all.
  • Dosages must be modified for use in children, pregnant and nursing women, and the elderly, as stated in the guidelines for antimicrobials 1.

Important Notes

  • If symptoms persist beyond the recommended timeframe, you should discontinue use and consult a healthcare provider as continued digestive issues may indicate a more serious condition requiring medical attention.
  • Antimicrobials, such as quinolones, are currently the empirical antimicrobials of choice for dysentery or identified infectious diarrhoea, but Pepto-Bismol is not a substitute for these medications 1.

From the Research

Duration of Pepto Bismol Treatment

  • The duration of Pepto Bismol (bismuth subsalicylate) treatment can vary depending on the condition being treated and the individual's response to the medication 2, 3.
  • For traveler's diarrhea, studies have shown that treatment with bismuth subsalicylate for up to 21 days can be effective in preventing the condition 4.
  • In the treatment of acute diarrhea, bismuth subsalicylate has been shown to be effective for short-term use, typically up to 48 hours 4.
  • However, it is recommended that treatment periods with any bismuth-containing compound, including Pepto Bismol, should last no longer than 6-8 weeks, followed by 8-week bismuth-free intervals to minimize the risk of intestinal absorption and sequestration of bismuth in multiple tissue sites 3.

Comparison with Other Treatments

  • A study comparing loperamide with bismuth subsalicylate for the treatment of acute traveler's diarrhea found that loperamide was a safe and effective alternative to bismuth subsalicylate, with fewer side effects 5.
  • Another study found that bismuth subsalicylate was effective in treating chronic infantile diarrhea and had beneficial effects on selected symptoms associated with Norwalk virus-induced gastroenteritis 2.

Important Considerations

  • The salicylate component of bismuth subsalicylate is responsible for its antisecretory effects in patients with diarrhea, while the bismuth component has direct antimicrobial effects 2, 6.
  • Bismuth subsalicylate has been shown to be effective in preventing traveler's diarrhea, with a success rate of 62-76% in preventing the condition 2, 4.

References

Guideline

Guideline Directed Topic Overview

Dr.Oracle Medical Advisory Board & Editors, 2025

Research

Bismuth subsalicylate in the treatment and prevention of diarrheal disease.

Drug intelligence & clinical pharmacy, 1987

Research

[Common gastrointestinal symptoms and their effective and safe treatment].

Ceska a Slovenska farmacie : casopis Ceske farmaceuticke spolecnosti a Slovenske farmaceuticke spolecnosti, 1999

Professional Medical Disclaimer

This information is intended for healthcare professionals. Any medical decision-making should rely on clinical judgment and independently verified information. The content provided herein does not replace professional discretion and should be considered supplementary to established clinical guidelines. Healthcare providers should verify all information against primary literature and current practice standards before application in patient care. Dr.Oracle assumes no liability for clinical decisions based on this content.

Have a follow-up question?

Our Medical A.I. is used by practicing medical doctors at top research institutions around the world. Ask any follow up question and get world-class guideline-backed answers instantly.