The Opium War 鸦片战争 =Yāpiàn zhànzhēng Opium has been known in China since the 7th century and for centuries it was used for medicinal purposes. It was not until the 17th century that the practice of mixing opium with tobacco for smoking was introduced into China by Europeans.
The import of opium into China stood at 200 chests (annual) in 1729, when the first anti-opium edict was promulgated. This edict was weakly enforced, and by the time Chinese authorities reissued the prohibition in starker terms in 1799, the figure had leaped; 4,500 chests were imported in the year 1800. The decade of the 1830s witnessed a rapid rise in opium trade,and by 1838 (just before the first Opium War) it climbed to 40,000 chests.The rise continued on after the Treaty of Nanking that concluded the war. source: wikipedia