Entomotoxicology is a relatively new branch of forensic entomology. The potential use of insects for detecting drugs and other toxins in decomposing tissues has been widely demonstrated. In death investigations, Diptera and other arthropods can be reliable alternate specimens for toxicological analyses in the absence of tissues and fluids normally taken for such purposes. Entomotoxicology also investigates the effects caused by drugs and toxins on arthropod development in order to assist the forensic postmortem interval estimates. However, several remarks on the limitations of entomotoxicology have been highlighted recently. In this paper, the implications for the practice of this forensic procedure are fully reviewed.