The taste of necrosis
Y'know, we normally seldom think about the taste of dying things. Most of the things we eat are already dead, and have been processed in a way that prevents decomposition, and we can taste it.
The taste of infection is something viscerally foul, and inescapable. I had a tooth that was rotting away for the past 2 weeks, and towards then end where the nerve itself became necrotic, I could taste it. It's similar to the times I get a tonsil infection and it's just so awful. It smells bad, tastes worse and drives you crazy.
Luckily, I got a root canal, and I am not only freed of the agony of a dying nerve, my breath no longer has that foul tastes in it. Which is good, I suppose.