This document provides an overview of toxicology and approaches to common poisonings and overdoses. It outlines clinical presentations and treatments for various physiologic stimulants and depressants, including anticholinergics, opioids, benzodiazepines, and more. Case scenarios exemplify how to recognize cholinergic, anticholinergic, and opioid poisonings based on symptoms and develop appropriate treatment plans focused on decontamination and supportive care.