A concoction is, strictly speaking, a combination of various ingredients, usually herbs, spices, condiments, powdery substances or minerals, mixed up together, minced, dissolved or macerated into a liquid so as they can be ingested or drunk. The term "concoction" is sometimes loosely used metaphorically in order to describe a cocktail or a motley assemblage of things, persons or ideas.
Quite often, various extremely pungent and spicy ketchups or hot sauces, usually based on Cayenne peppers, are inadvertently (or for marketing reasons) called "concoctions".
Ahat that is used by magicians (usually to do magic tricks). A bandage that can be used cover cut skin (usually cut places).