''Biocompatible is a process, an object, a factor that does directly or indirectly, in the short, medium or long term, no negative effect on health or the balance of a living organism.
It obeys the Hippocratic principle "primum non nocere." A fortiori is biocompatible anything that maintains or improves health status.''

Definition taken from a text by the World Health Organization
"primum non nocere" : First, do no harm