The United States has supported drug crop eradication and alternative development programs in the Andes for decades. Colombia, Bolivia, and Peru collectively produce nearly the entire global supply of cocaine. In addition, Colombia has become a producer of high quality heroin, most of it destined for the United States and Europe. The United States provides counternarcotics assistance through the Andean Counterdrug Initiative (ACI). The program supports a number of missions, including interdiction of drug trafficking, illicit crop eradication, alternative development, and rule of law and democracy promotion. From FY2000 through FY2005, the United States has provided a total of about $4.3 billion in ACI funds. Since 2001, coca cultivation in the Andes has been reduced by 22%, with the largest decrease occurring in Colombia, according to the State Department. Opium poppy crops, grown mainly in Colombia and from which heroin is made, have been reduced by 67%. However, the region was still capable of producing 640 metric tons of cocaine, and 3.8 metric tons of heroin in 2004, according to the White House Office of National Drug Control Policy. Congress has expressed a number of concerns with regard to eradication, especially the health and environmental effects of aerial spraying, its sustainability and social consequences, and the reliability of drug crop estimates. With regard to alternative development, Congress has expressed interest in its effectiveness, its relationship to eradication, and the long-term sustainability of programs once they are started. Drug crops are eradicated either manually or by aerial spraying of a herbicide mixture, the main ingredient being glyphosate, used commercially in the United States under the brand name of Roundup?. Eradication can be conducted with the voluntary agreement of growers, or involuntarily. Peru and Bolivia do not allow aerial eradication, which has proven to be controversial. Critics believe it poses risks to the environment and the health of inhabitants living in sprayed regions. Proponents believe it is the most effective and safe means to defoliate large areas being used for drug crop cultivation, thereby removing a lucrative source of income from the illegally armed Colombian groups. Providing alternatives to drug crops is believed to be crucial to achieve effective eradication. This often includes technical support for farmers, marketing assistance, and strengthening the transportation infrastructure in order to get crops to market. The U.S. approach to alternative development (AD) is to link it to eradication. Growers who agree to eradicate are eligible for assistance. This report will not be updated. For more information on the Andean Counterdrug Initiative, see CRS Report RL32337, Andean Counterdrug Initiative (ACI) and Related Funding Programs: FY2005 Assistance; and CRS Report RL32774, Plan Colombia: A Progress Report, both by Connie Veillette.