Andrographis paniculata is a plant that has been effectively used in traditional Asian medicines for centuries. Its perceived “blood purifying” property results in its use in diseases where blood “abnormalities” are considered causes of disease, such as skin eruptions, boils, scabies, and chronic undetermined fevers. The aerial part of the plant, used medicinally, contains a large number of chemical constituents, mainly lactones, diterpenoids, diterpene glycosides, flavonoids, and flavonoid glycosides. Controlled clinical trials report its safe and effective use for reducing symptoms of uncomplicated upper respiratory tract infections. Since many of the disease conditions commonly treated with A. paniculata in traditional medical systems are considered self-limiting, its purported benefits need critical evaluation. This review summarizes current scientific findings and suggests further research to verify the therapeutic efficacy of A. paniculata. A. paniculata, known on the Indian subcontinent as Chirayath and Kalmegh in Urdu and Hindi languages, respectively, is an annual plant, 1-3 ft high, that is one of the most commonly used plants in the traditional systems of Unani and Ayurvedic medicines. It is called Creat in English and is known as the “king of bitters.” It grows in hedgerows throughout the plains of India and is also cultivated in gardens.1,2 It also grows in many other Asian countries and is used as a traditional herbal medicine in China, Hong Kong, the Philippines, Malaysia, Indonesia, and Thailand. The aerial parts are most commonly used; however, the whole plant or roots are mentioned for certain limited purposes in some manuscripts. Traditionally, the plant was used as an infusion, decoction, or powder, either alone or in combination with other medicinal plants. In modern times, and in many controlled clinical trials, commercial preparations have tended to be standardized extracts of the whole plant. Since many disease conditions commonly treated with A. paniculata in traditional medical systems are considered self-limiting, its purported benefits need critical evaluation. This review summarizes current scientific findings and suggests areas where further research is needed.