Chinese alchemical elixir poisoning
In Chinese alchemy, elixir poisoning refers to the toxic effects from elixirs of immortality that contained metals and minerals such as mercury and arsenic. The official Twenty-Four Histories record numerous Chinese emperors, nobles, and officials who died from taking elixirs to prolong their lifespans.
Source: Wikipedia — Chinese alchemical elixir poisoning (CC BY-SA 4.0)