Abstract Hylomecon japonica (Thunb.) Prantl & Kündig (Papaveraceae) has a rich history of traditional medicinal uses, particularly in the treatment of bruises, rheumatism, and various ailments. Recent studies have identified alkaloids, saponins, terpenes, phenols, flavonoids, and other compounds in the plant, all of which demonstrate significant pharmacological effects such as anti‐inflammatory and anti‐tumor properties. While currently valued for its use in wetland plant landscapes and as a garden design color enhancer, ongoing research on the chemical composition and pharmacological properties of Hylomecon japonica is uncovering its potential medical applications. This paper provides a comprehensive review of extraction and separation methods, chemical components, and pharmacological activities of these compounds to further explore the medicinal potential of Hylomecon japonica .