Forensic Medicine as an auxiliary science in the administration of Justice elaborates expert reports attached to the regulations that are derived from the legal regulations, in the country however the ignorance of medical science and health by legislators has caused them to develop laws that hinder the expert work, medical science has been assumed as an exact science to summarize the diseases to numerical factors.This essay aims to analyze from a medical-legal perspective the coupling that the law and criminal law regulations should have with medical science so that it can inform the administrators of justice in an adequate, practical and clear way, sticking to the historical truth and becoming a scientific instrument at the service of Justice and society. Medical science is a branch of inexact scientific knowledge that is marked by the existence of multiple factors that make the evolution of an illness or trauma sometimes unpredictable.