In vivo

adv. in the living organism

In vivo (Latin: (with)in the living) means that which takes place inside an organism. In science, in vivo refers to experimentation done in or on the living tissue of a whole, living organism as opposed to a partial or dead one. Animal testing and clinical trials are forms of in vivo research.
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Adjective
1. within a living organism; "in vivo techniques"
(antonym) in vitro, ex vivo
(classification) biology, biological science
Adverb
1. in the living organism; "studies conducted in vivo"

In the living organism.

In the body. The opposite of in vitro (outside the body or in the laboratory).