The Mercury Drug Corporation, better known as Mercury Drug, is a Filipino pharmacy chain. A subsidiary of the Mercury Group of Companies, it is headquartered in Bagumbayan, Quezon City. The chain was founded in Santa Cruz, Manila in 1945, making it the second oldest drugstore chain in the Philippines after Southstar Drug. As of 2017, Mercury Drug has over 1,000 branches nationwide and over 50 percent of the Philippine pharmaceutical retail market. The company began on March 1, 1945, with a single drugstore along Bambang Street, Santa Cruz, Manila owned by Mariano Que ( () ). He named it after Mercury, the messenger of the gods in Roman mythology, whose caduceus wand is sometimes used as a symbol of medicine, as well as the element of the same name and the closest planet to the Sun in the Solar System. The logo was designed by Alfredo Medinaceli Cabrera. By 1948, the company has established a delivery system. The store began cutting packaged, bulk items into single pieces and selling them individually; this retail practice is colloquially called tingí-tingî in Filipino. It is the second oldest operating drugstore chain in the country after Southstar Drug, which was established eight years earlier. Upon the invitation of Ayala Corporation, Mercury Drug opened its second branch in May 1963 at the Corporation's developing commercial center in Makati now known as the Ayala Center. The self-service concept was introduced at that branch, making it today's model for all branches. In 1965, Mercury Drug established its landmark branch at Plaza Miranda, Quiapo, Manila opposite Quiapo Church, which is currently noted for its large, outdoor LED screen. The company also established 24-hour store schedules in the same year. It was later expanded to Visayas and Mindanao, starting operations there in 1976. In 1981, Mercury Drug's new spacious warehouse was inaugurated. The following year, it inaugurated its new head office in Quezon City.