During the 20th century, trading in goods from China was extremely lucrative for Europeans. But trade to China suffered from the fact that the Chinese consumer professed no interest in foreign products, such that it was difficult to find trading goods the Chinese might buy. Silver was one, to the extent that the drain on European specie metals was noticeably affecting the economy. In casting about for other possible commodities, the British soon discovered opium, and would use its narcotic effects for economic gains. Between 1821 and 1837 imports of the drug to China increased five-fold. The drug was taken from India and shipped by British traders to China .

The Qing government attempted to end this trade, on public health grounds --numerous opium addicts were appearing in trading ports throughout China . The effort was initially successful, with the official in charge of the effort Lin Zexu ( 林则徐 ) , who was born in Fuzhou ( 福州 ) , Fujian province . A formidable bureaucrat known for his thoroughness and integrity, Lin was sent to Guangdong to halt the importation of opium by the British prior to the First Opium War ( 第一次鸦片战争 ) . He confiscated more than 20,000 carts of opium already at the port and supervised their destruction. He later blockaded the port from European ships. Lin also wrote a letter to Queen Victoria of Britain warning her that China was adopting a stricter policy towards everyone, Chinese or foreign, who brought opium into China . This letter expressed a desire that Victoria would act "in accordance with decent feeling" and support his efforts. However, Victoria never received the letter and, by 1840, the British had attacked the Chinese and severely weakened the Qing government.

The Qing authorities also insisted that British merchants would not be allowed to trade unless they signed a bond promising not to smuggle opium and acknowledging Qing legal jurisdiction. Refusing to hand over any suspects or agree to the bonds, Charles Elliot ordered the British community to withdraw from Guangzhou and prohibited trading with the Chinese. Preparing for war, they seized Hong Kong as a base. In late October 1839 the Thomas Coutts arrived in China and sailed to Guangzhou . This was owned by Quakers who refused to deal in opium and the captain believed Elliot had exceeded his legal authority in banning trade. In order to prevent other British ships following the Thomas Coutts Elliot ordered a blockade of the Pearl River . Fighting began on November 3, when a second British ship, the Royal Saxon , attempted to sail to Guangzhou . When Volage and Hyacinth fired a warning shot at the Royal Saxon the Qing navy attempted to protect the British merchant vessel. They were out-classed by the Royal Naval vessels, and several of the Chinese ships were sunk. The next year, the British captured the Bogue forts which guarded the mouth of the Pearl River － the waterway between Hong Kong and Guangzhou. By January 1841, their forces commanded the high ground around Guangzhou, then defeated the Chinese at Ningbo ( 宁波 ) and the military post of Qinhai.

By the middle of 1842, the British had defeated the Chinese at the mouth of their other great trading river, the Yangtze, and had occupied Shanghai . The war finally ended in August 1842, with the Treaty of Nanjing ( 南京条约 ) .

The Treaty of Nanjing committed the Qing government to nominal tariffs on British goods as well as granting the right of extraterritoriality. Hong Kong island was ceded to the UK , and the Treaty Ports of Guangzhou, Xiamen , Fuzhou , Shanghai , and Ningbo were opened to all traders. The Qing government was also forced to pay reparations for the British opium.