Harm reduction is the main objective of care for all drug users especially injected drug users (IDUs) because they are a high risk for HIV infection, hepatitis C, and tuberculosis. In Thailand, drug policies aim to force drug users to abandon illicit drugs and by substitution with Methadone. Thai drug policies are not effective because the services are not comprehensive and fail to encourage drug users to access the health service system. The drug users’ database and understanding of drug use in Thailand are out of date. In addition, analysis and synthesis of data are lacking. Drugs policies are usually a product of reaction to drug problems rather than bored on reliable information, due to the time needed for data collection. A possible solution is to conduct Rapid Situation Assessment (RSA). RSA is a highly effective tool for data collection and for 1) finding and analyzing existing information, 2) conducting interviews, 3) questioning, and 4) drawing conclusion and making policies. The success of RSA required the cooperation of all participants, including drug user, police, family members, policy makers, health providers, courts and the community. Better information leads to better policies.