Background: Medicinal plants are widely used to treat infectious diseases, metabolic disorders and cancer. Argemone mexicana L. (A. mexicana), commonly found on desolate land of Marathwada (Maharashtra, India) has been used to treat oral cavity infections. Methods: In this study, cold aqueous and methanolic extracts were prepared from A. mexicana stem and leaves. These extracts were tested for their antifungal and anticancer activities. The antifungal activity was tested using the agar well diffusion method, while the anticancer activity against immortalized cell lines was assessed by trypan blue assay. Results: It was observed that both cold aqueous and methanolic extracts of A. mexicana stem and leaves inhibited the growth of Mucor indicus, Aspergillus flavus, Aspergillus niger and Penicillum notatum. Antifungal activity of the extract was comparable to that of Amphoterecin-B. A. mexicana extracts had a cytotoxic effect on A549, SiHa and KB immortalized cell lines that were similar to that of berberine. Conclusion: The A. mexicana leaf and stems exhibit strong antifungal and anticancer potential.