Medical Use of Bismuth: the Two Sides of the Coin

Bismuth is a heavy metal and was regarded until recently to be the heaviest stable element. It was discovered around ten years ago that the only natural isotope of bismuth, 209Bi, is an alpha emitter with a halflife of 1.9 x 1019 years [1]. Due to the low stability in aqueous solutions of bismuth derivatives with the oxidation number +V, bismuth with the oxidation number +III is regarded as the only relevant bismuth species in biological systems [2]. Bismuth is seen as the least toxic heavy metal for humans and is widely used in medical applications for its good antibacterial properties [3]. Bismuth-containing pharmaceuticals are most commonly used in the eradication of Helicobacter pylori, the causative agent for diseases like gastritis, peptic ulcer and even gastric cancer [4]. Recent evidence of bismuth methylation by human gut microbiota, resulting in more mobile and presumably more harmful derivatives, has led to new efforts to evaluate the usage of bismuth under this newfound aspect [5]. This minireview presents our current knowledge of the rare element bismuth, in particular its use in medicine, and highlights the potential health risk associated with its application.