What was the first illegal drug ever made?

The trade of drugs has existed for as long as the drugs themselves have existed. However, the trade of drugs was fully legal until the introduction of drug prohibition. The history of the illegal drug trade is thus closely tied to the history of drug prohibition. In the First Opium War, the United Kingdom forced China to allow British merchants to trade in opium with the general population of China. Although illegal by imperial decree, smoking opium had become common in the 1800s due to increasing importation via British merchants. Trading in opium was (as it is today in the heroin trade) extremely lucrative. As a result of the trade an estimated two million Chinese people became addicted to the drug. The British Crown (via the treaties of Nanking and Tianjin) took vast sums of money from the Chinese government in what they referred to as 'reparations' for the wars.