Sneezing powder is a group of powders or powder-like substances that induce sneezing when someone is exposed to them. This is usually done as a practical joke or prank to an unsuspecting victim.
Sneezing powders containing Veratrum album alkaloids have been linked to poisoning, including upset stomach, fainting, slowed heart rate and low blood pressure.[1] Children are especially vulnerable.[2]
An example of a (sneeze-inducing) agent is helenalin (the acetate is called angustibalin). The plant containing this chamissonolide is actually eponymously called sneezeweed.