One of the least publicised of the CIA's activities is its support for the heroin business in Southeast Asia. In carrying out its task of 'fighting communism' the CIA has supported allies whose interest in the fight is only partial —their prime concerns have been merely to survive (as in the case of Meo tribes men in Laos, for example) or to make enormous profits from the sale of heroin on an international scale (in the case of the Kuomintang). By assisting these groups the CIA has, ironically, implicated itself in the very criminal activity that the United States government and its agencies have pledged themselves to combatting. In terms of the numbers of people, national governments, and money involved, the CIA's support for the heroin business must be one of its most extensive operations, and almost certainly one of its most compromising.

Alfred McCoy has written: 'American diplomats and secret agents have been involved in the narcotics traffic at three levels (1) coincidental complicity by allying with groups actively engaged in the drug traffic; (2) abetting the traffic by covering up for known traffickers and condoning their involvement.(3) and active engagement in the transport of opium and heroin.' (1)