In movies and TV you see heroin users insert a needle, pull blood out, and then inject. 1. Is that how people really do it, and 2 why do they mix blood first?

Question

In movies and TV you see heroin users insert a needle, pull blood out, and then inject. 1. Is that how people really do it, and 2 why do they mix blood first?

In: Biology

Answer 1

Its to ensure the needle is in a vein. Medical professionals do the same thing when inserting an IV cannula.