<p><i>Phlogacanthus</i> is a genus within the Acanthaceae family. Its disjunct distribution spans several countries, including Bangladesh, Vietnam, Thailand, India, and Bhutan. Medicinal folklore has long used species of this genus to treat fever, cough, diarrhea, and stomachache. Plants of this genus are grown for their aesthetic qualities, as well as for their edible flowers and leaves. This genus contains diverse classes of phytochemicals, including diterpenes, triterpenoids, flavonoids, alkaloids, and others. Diterpenoids represent the predominant class, with Abietane (14), Lactone (13), and Ent-abietane (8) diterpenoids being particularly prevalent in <i>Phlogacanthus</i> species. There have been reports of their cytotoxic, antioxidant, analgesic, and anti-inflammatory properties in both their extract and pure isolated compounds. Nearly all the structures of the compounds that have been identified from <i>Phlogacanthus</i> species to date are provided. The comprehensive chemical diversity and complexity of <i>Phlogacanthus</i> species are represented by identifying a number of important natural compounds with many connections in an intricate phytochemical network. This comprehensive review primarily highlights the traditional uses, phytochemistry, and biological activities of <i>Phlogacanthus</i> species to assess their therapeutic potential and prospects for further research.</p> Graphical abstract <p></p>