We conducted a qualitative study to determine the range of promotional practices influencing drug usage in Mumbai. Open-ended interviews were conducted with 15 senior executives in drug companies, 25 chemists and 25 doctors; focus group discussions were held with 36 medical representatives. The study provided a picture of what might be described as an unholy alliance: manufacturers, chemists and doctors conspire to make profits at the expense of consumers and the public's health, even as they negotiate with each other on their respective shares of these profits. Misleading information, incentives and unethical trade practices were identified as methods to increase the prescription and sale of drugs. Medical representatives provide incomplete medical information to influence prescribing practices; they also offer incentives including conference sponsorship. Doctors may also demand incentives, as when doctors' associations threaten to boycott companies that do not comply with their demands for sponsorship. Manufacturers, chemists and medical representatives use various unethical trade practices. Of particular interest was the finding that chemists are major players in this system, providing drug information directly to patients. The study also reinforced our impression that medical representatives are the least powerful of the four groups.