Purpose of Review <p><i>Argemone mexicana.</i> L., commonly known as Mexican poppy, is a widely distributed plant with diverse toxic and biomedical properties. The present review summarized the recent findings about pharmacological activities of its secondary metabolites; its underlying mechanism of action and potential therapeutic applications. Its initial recognition as plant causing “Epidemic Dropsy,” necessitate investigation for potential phytochemicals.</p> Recent Findings <p>The major toxic substances, benzophenanthridine and isoquinoline alkaloids studied for their extraction, separation, and clinical impact. Besides, role in toxicity, chelerythrine, sanguinarine, berberine, protopine, have potential pharmacological effects, including antimicrobial, anticancer, antioxidant, anti-inflammatory, and antihelminthic activities. Overall, <i>A. mexicana</i> has dose-dependent toxicological effects as well as pharmacological potential.</p> Summary <p>This review focuses on systemic details, history, secondary metabolites, extraction, and biological, pharmacological, and toxicological potential. Future research is necessary to focus on its anonymous metabolites and synergistic effect with existing drugs that may improve its efficacy and therapeutic range.</p> Graphical Abstract <p></p>