Ageratum conyzoides L., commonly known as goat weed or billygoat weed, belongs to the Asteraceae family and is an annual aromatic herb found in tropical and subtropical regions worldwide. It has a rich history of traditional medicinal uses. Extracts from Ageratum conyzoides contain essential oils and secondary metabolites with diverse pharmacological potentials, including medication, drug discovery, and development. This article provides a comprehensive review of Ageratum conyzoides, focusing on its active phytoconstituents responsible for its various pharmacological and agricultural applications. The herb is also noted for its efficacy in monitoring aflatoxin contamination in feed and food, thereby safeguarding stored products.