Bismuth-based drugs have long been used for the treatment of Helicobacter pylori infection. In this work, the metal content in H. pylori was monitored at the single-cell level by time-resolved inductively coupled plasma mass spectrometry, and similar to 2.9 x 10(7) Mg atoms/cell was determined for the wild-type. Bacteria treated with a Bi antiulcer drug deposited nearly 1.0 x 10(6) Bi atoms/cell, whereas the uptake process took similar to 3 h to reach the half-maximum. Interference of ferric ions on bismuth uptake was demonstrated, suggesting that the metallodrug can utilize certain iron-transport pathways in the pathogen. The approach provides a general strategy for monitoring metals in single cells, facilitating exploration of metal-relevant bioprocesses.