Western countries exports opium from India to China

Following the Portuguese, other Western countries found they could obtain opium grown in India for a cheap price and sell it in China at a considerable profit. In the process Western sailors experimented with smoking opium. This was originally considered barbaric and subversive by the Chinese but eventually caught on and spread through the Chinese population creating a new, much larger demand for opium.

Whereas in 1729 about 200 chests of opium were imported into China, by 1767 this had grown to 1,000 chests and by 1838 more than 40,000 chests were being imported each year.

The profits from this enlarged opium trade allowed the European nations to purchase Chinese luxury goods (such as tea, porcelain or silk) that were in high demand in the West without paying so much in New World silver controlled largely by Spain.

Source: https://ocw.mit.edu/ans7870/21f/21f.027/rise_fall_canton_01/pdf/cw_essay.pdf

Drugs: Opium (morphine, heroin, opioids)
Regions: China, India, Europe, Netherlands, Portugal, UK (England, Scotland, Wales, Northern Ireland)
Topics: Cultivation, production and trade