How to murder a quack?

[Crazed Rabbit]

Tell the quack that his life can be bettered by a simple chemical compound application, similar to aroma therapy. Advise a combination of nitrates, often found in plant fertilizer, and a specific fractional distillate of certain long chains of hydrocarbons. Have him make several liters, then light it for a soothing experience that will make all his worldly problems fade away.

CR

EDIT: I'm sure there's some chemicals that make you throw up violently. Consider containment in a gel capsule so the pills can be taken before a fancy dinner of sorts (a scientific lecture would be best) and then dissolve.