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Bismatrol Maximum Strength Side Effects

Generic name: bismuth subsalicylate

Medically reviewed by Last updated on Sep 14, 2022.

Note: This document contains side effect information about bismuth subsalicylate. Some dosage forms listed on this page may not apply to the brand name Bismatrol Maximum Strength.

Applies to bismuth subsalicylate: oral capsule liquid filled, oral suspension, oral tablet, oral tablet chewable.

Serious side effects

Along with its needed effects, bismuth subsalicylate (the active ingredient contained in Bismatrol Maximum Strength) may cause some unwanted effects. Although not all of these side effects may occur, if they do occur they may need medical attention.

Check with your doctor immediately if any of the following side effects occur while taking bismuth subsalicylate:

In some patients bismuth subsalicylate may cause dark tongue and/or grayish black stools. This is only temporary and will go away when you Stop taking bismuth subsalicylate.

  • Anxiety
  • any loss of hearing
  • confusion
  • constipation (severe)
  • diarrhea (severe or continuing)
  • difficulty in speaking or slurred speech
  • dizziness or lightheadedness
  • drowsiness (severe)
  • fast or deep breathing
  • headache (severe or continuing)
  • increased sweating
  • increased thirst
  • mental depression
  • muscle spasms (especially of face, neck, and back)
  • muscle weakness
  • nausea or vomiting (severe or continuing)
  • ringing or buzzing in ears (continuing)
  • stomach pain (severe or continuing)
  • trembling
  • uncontrollable flapping movements of the hands (especially in elderly patients) or other uncontrolled body movements
  • vision problems

For Healthcare Professionals

Applies to bismuth subsalicylate: compounding powder, oral capsule, oral suspension, oral tablet, oral tablet chewable.

Nervous system

Rare (less than 0.1%): Myoclonic encephalopathy

Frequency not reported: Weakness, fatigue, depression, anxiety, irritability, insomnia, unsteady gait, motor incoordination, loss of memory, jerky movements, mental confusion, disorientation, difficulty in walking and speaking, tremor, myoclonic jerks, incontinence[Ref]

Nervous system toxicity is a common feature of bismuth toxicity. Bismuth toxicity is characterized by the insidious onset of weakness and fatigue, depression, anxiety, irritability, insomnia, unsteady gait, motor incoordination, loss of memory, and jerky movements. Acute toxicity may result in the development of mental confusion, disorientation, difficulty in walking and speaking, tremor, myoclonic jerks, and incontinence.

Myoclonic encephalopathy has occurred in patients who have ingested bismuth for several months to years, but the incidence is very rare. Recovery of patients from bismuth encephalopathy may take several months following discontinuation of use. Bismuth encephalopathy has generally been reported in patients ingesting salts other than subsalicylate.[Ref]


Salicylism has been reported in patients who chronically ingest bismuth subsalicylate (the active ingredient contained in Bismatrol Maximum Strength) Common complaints include vertigo, diminished hearing, lethargy, CNS dysfunction, confusion, tinnitus, vomiting, and abdominal pain. Patients may present with respiratory alkalosis and metabolic acidosis, azotemia, and hypoprothrombinemia and platelet dysfunction. The elderly may be particularly vulnerable to the development of salicylism.[Ref]

Frequency not reported: Salicylism[Ref]


Very common (10% or more): Black stool

Common (1% to 10%): Black tongue

Frequency not reported: Nausea, vomiting[Ref]

Frequently asked questions


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8. Supino-Viterbo V, Sicard C, Risvegliato M, Rancurel G, Buge A. Toxic encephalopathy due to ingestion of bismuth salts: clinical and EEG studies of 45 patients. J Neurol Neurosurg Psychiatry. 1977;40:748-52.

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10. Salicylate in pepto-bismol. Med Lett Drugs Ther. 1980;22:63.

11. DuPont HL. Bismuth subsalicylate in the treatment and prevention of diarrheal disease. Drug Intell Clin Pharm. 1987;21:687-93.

12. Bierer DW. Bismuth subsalicylate: history, chemistry, and safety. Rev Infect Dis. 1990;12 Suppl 1:s3-8.

13. Gordon MF, Abrams RI, Rubin DB, Barr WB, Correa DD. Bismuth toxicity. Neurology. 1994;44:2418.

14. Vernace MA, Bellucci AG, Wilkes BM. Chronic salicylate toxicity due to consumption of over-the-counter bismuth subsalicylate. Am J Med. 1994;97:308-9.

15. Sainsbury SJ. Fatal salicylate toxicity from bismuth subsalicylate. West J Med. 1991;155:637-9.

16. Cerner Multum, Inc. UK Summary of Product Characteristics.

Further information

Always consult your healthcare provider to ensure the information displayed on this page applies to your personal circumstances.

Some side effects may not be reported. You may report them to the FDA.