This paper presents the experience of "La Casa" Programme, a center of the University of Los Andes (Bogotá, Colombia) aimed at prevention, treatment, and research in the fields of drug addiction and AIDS. The multimodal strategy at "La Casa", ambulatory and almost free of charge, has constituted a unique approach in Colombia. The country has a heavy and specific drug consumption problem: in the last ten years the number of regular consumers of a mixture of alcohol, coca paste ("basuco")/cocaine and marihuana has increased to almost 500,000 people; state facilities and human resources are scarce, thus the importance of an appropriate use of them and search for alternatives.