Nutmeg/Mace

Nutmeg is frequently used as a cocktail garnish and sometimes as an ingredient in flavored spirits and liqueurs. Mace is the spice made from the reddish seed covering (aril) of the nutmeg seed.

A large quantity of nutmeg can cause intense nausea, dizziness, extreme dry mouth, and a lingering slowdown of normal brain function, but this is at around 2 tablespoons and above [link], far above what is typically used in food or beverages.

Further Reading:

"My Nutmeg Bender: The surprising intoxicant hidden in your spice rack" The Atlantic [link]

"A Warning on Nutmeg" The New York Times [link]