I bet you are all familiar with the Opium Wars. For those not versed, these were wars the East India Company waged against the Chinese Empire of old, managing to make the Chinese Emperor to capitulate to the demands of the brits.
The war was started mainly because the brits traded heavily with China importing large amounts of porcelain and tea, but because of the heavy restrictions on trade with foreigners that China had at the time, the british empire was losing enormous amounts of money because of this and the chinese weren't willing to give a favorable treatment to a loyal customer like the brits. And so the British Empire had to come up with something the chinese wanted really bad. Something that they could sell in bulk at high prices in order to make their money back: Opium. The East India Company started to smuggle opium in China by the tons through the former chinese border with India. The problem is that the chinese government was waging a war against opium at the time because large amounts of the population of all strata were addicted. This didn't fared well to the brits because soon the chinese started to arrest smugglers and burning hundreds of pounds of opium, making the East India Company lose inmense amounts of money and they demanded compensation for the destroyed goods from the chinese. The chinese said no and imposed heavier trade restrictions on the british traders, as well as arresting several on suspicion of smuggling opium, and because of this, the first Opium War begun. Hilariously enough, the chinese lost the war mainly because large amounts of the army were addicted to opium.
This also created the period known in China as "The 100 years of shame" in which China was at the mercy of Britain on nearly everything, but most importantly, on trade. And it all begun because the anglos pushed drugs on the chinks to break even.