Not as big as the Kuomintang ahem I mean Green Gang ...
"With the fall of the Qing Dynasty in 1911 and the growth of drug addiction in China, criminal elements began moving into Shanghai's foreign concessions in great numbers. Since extraterritorial rights granted the Western powers were still in operation, Chinese living in these concessions were subject only to that particular concession's laws.
Among the many groups to exploit this situation was the 'Green Gang', which occupied the French concession and conducted its vice operations undisturbed by the French government. A Green Gang member named Du Yuesheng eventually unified all the gangs into a syndicate trafficking in drugs. Tu came to be known as the Opium King, and was one of three bosses who were referred to as the Big Three.
The Green Gang syndicate was a thriving organisation in 1927, when Guomindang troops and Communist contingents marched north on an expedition to rid the country of warlords. On his approach to Shanghai Chiang Kai-shek, who was anxious to rid himself of the Communists, contacted Du Yuesheng for help. Du responded by recruiting thousands from Shanghai's underworld. When the workers' unions closed down the city in a massive strike to honour Chiang's victory, the thugs swarmed out of the French concession and fell on Communists, labour union members and innocent bystanders alike. Thousands were slaughtered in this bloody massacre.
After gaining control of China, Chiang continued his association with the Green Gang. He enlisted the Big Three as honorary advisers to his government and named Du Yuesheng a major general in the army. The drug traffic went on unabated not only in China, but as far away as the United States, where Shanghai heroine was being distributed by the Mafia.
In 1937, when Japan launched her invasion of China, the Guomindang retreated to Chongqing in Sichuan province.
Although to all appearances Chiang and the Japanese militarists were at war, a great deal of trade took place between the invaders and the Nationalist Government; much of this traffic involved opium.
Japan had made opium a basic source of her revenue in the occupied territories. Chiang (with the help of Du Yuesheng) supplied the drug to Japan. Vast fields of red, pink and white poppies covered the foothill districts of Sichuan and Yunnan provinces, and great opium shipments travelled down the Yangzi to Shanghai, or over the Burma road to Southeast Asia.
After the Japanese defeat, civil war between the Guomindang and the Communists resumed. As the Communists swept south to Shanghai, the Green Gang and other criminal syndicates fled to Hong Kong; the Guomindang escaped to Taiwan. The People's Republic of China was founded.
By this time, there were literally millions of addicts in the country. The new government immediately set about coping with the monumental problem. Peasants were persuaded to plough in their opium crops and sow wheat or rice instead. Neighbourhoods were mobilised in a massive educational programme. The street committees which governed the neighbourhoods held study groups in which the evils of opium and heroin were discussed. Families of known addicts were educated not to blame their addict members, but to encourage them to seek help. Addicts themselves were impressed by the fact that they were not blamed for their addiction, since they were considered victims of foreign governments and other enemies of the people. After their cure, they were given training and then placed in paying jobs. Many of them were hired by the government to work with other addicts.
At the same time, pressure was placed on the dealers. Those who surrendered were accepted by the community, re-educated, trained for meaningful work and given jobs. The rest were packed off to prison, and the worst offenders were executed.
By 1956, the People's Republic of China had virtually eliminated its drug problem.
From time to time, the Taiwan press has accused the People's Republic of smuggling opium across the border of Yunnan province into Southeast Asia. Such accusations are particularly curious in the light of the well-publicised fact that most of the opium traffic in these countries is carried on by remnants of the Guomindang forces. Fleeing across the border at the time of the Civil War, these forces expanded the cultivation of opium and monopolised the traffic until now they are known as the opium barons of the region.
As for any smuggling from Yunnan, the Shan tribesmen of the Burma hill countries - who know all the mountain trails - deny this vigorously. Some of the Shans are anti-Communists who have been employed as spies by the CIA. Between 1962 and 1967, these people penetrated deep into China's Yunnan province on espionage missions. They reported that legitimate agricultural crops were being grown in places where formerly there had been extensive poppy fields. But of poppy cultivation, they saw not a trace."
http://www.sacu.org/opium.html
Mao Zedong and the CCP were big producer of opium. from Jiangxi–Fujian Soviet to Shaanxi Yan'an, the CCP central command and their local forces grew and sold opium to finance their operations. according to Soviet representative to Yan'an, Peter Vladimirov in his book ( the Yan'an diaries ). he discovered that the CCP forces grew opium and sold them to Japanese-occupied Chinese territories during the 2nd Sino-Japanese war. he questioned Mao Zedong about it, and the latter acknowledged it. according to Mao. it was not an honorable thing but he really had no choice, they badly needed the money and the opium profits were good. that's the typical example of the CCP hypocrisy in its history. they condemned the warlords for growing and selling opium to poison Chinese people but they did the same things as them, even worse
