Can bismuth exposure cause neurological and kidney toxicity?

Bismuth exposure is most clearly documented from oral medicines and can occur from certain supplements and cosmetics; workplace exposure is credible but less well quantified. For an 84-year-old, reduced renal reserve or unrecognized kidney impairment may increase concern because absorbed bismuth is cleared substantially through the kidneys.

Exposure sources

• Medicines: Oral products such as bismuth subsalicylate release bismuth in the gastrointestinal tract. Although <1% may be absorbed, elimination is mainly urinary and biliary, with a reported terminal half-life of 21–72 days, allowing accumulation with prolonged or excessive use.
• Supplements: Bismuth-containing products, including bismuth subgallate, have produced elevated serum and urinary bismuth in case reports, chiefly with extended or excessive intake.
• Cosmetics: A bismuth-citrate scalp/hair formulation showed measurable dermal uptake—0.49 ± 0.08 µg/cm², approximately 0.83 ± 0.13% of the applied dose. This finding is formulation-specific.
• Occupational materials: Handling or inhaling bismuth-containing dusts is a plausible route, but direct air-exposure-to-body-burden data are insufficient.

Toxicity and mechanism

• Neurologic toxicity: Chronic substantial exposure can cause bismuth encephalopathy, including confusion, memory or behavioral change, ataxia, dysarthria, myoclonus, and sometimes seizures. Reported cases had blood bismuth 50–1,600 μg/L and urine 150–1,250 μg/L; these are case ranges, not validated thresholds.
• Kidney toxicity: Large medicinal exposures can cause acute kidney injury, particularly proximal tubular injury/acute tubular necrosis and sometimes Fanconi-type dysfunction. Persistent impairment has occurred in severe cases.
• Absorbed bismuth is excreted in urine; elevated urinary bismuth supports systemic absorption but does not alone establish toxicity.

Bottom line

• The claim is substantially supported: medicines are the best-established source; supplements and certain cosmetics can contribute; occupational exposure is plausible. Excessive exposure can cause serious neurologic and renal toxicity, so new neurologic symptoms or rising creatinine during bismuth use warrant stopping exposure and prompt clinical evaluation.