Oral toxicity of bismuth in rat: single and 28-day repeated administration studies.

The consumption and production of bismuth are increasing, however there is very little information about the direct toxic effect of bismuth. The present study aimed to characterize the potential toxic effects of bismuth through oral administration and observation for fourteen days following single dose of 0 and 2,000 mg/kg (acute oral toxicity study), and repeated oral administration for twenty-eight days at dose levels of 0, 40, 200, and 1,000 mg/kg daily (28-d repeated oral dose toxicity study) to male and female Crj:CD (SD) IGS rats (SPF). We found no deaths and no abnormalities in clinical signs, body weights, and necropsy findings for any of the animals in the acute oral toxicity study and no changes attributable to bismuth in either males or females in the dose group up to 1,000 mg/kg of the 28-d repeated-dose toxicity study. Therefore, we determined that the lethal dose with a 50% mortality rate (LD50) is greater than 2,000 mg/kg and the no-observed-adverse-effect level (NOAEL) of bismuth is 1,000 mg/kg in both sexes. We conclude that the adverse toxic effects of bismuth as a simple metal substance are low compared to lead toxicity under the conditions tested in our studies.