Scientific investigation can reveal facts concerning drug use but personal and social values are also important to determine whether the probable consequences outlined by the facts are good or bad. In the decision-making process, the happiness of society's members and the functioning of society are other costs to be weighed. The two types of drug problems involved here are the individual medical problem and the social problem. The social problem is created when the use of substances puts some members of society into conflict with the rest of society. Scientific fact can shed light on how best to treat a medical problem. The social problem can be handled by examining the conflict in light of what is fact and what is value judgment. There are three factors which go into this decision-making process. Scientific fact is an area for the experts and for the public to determine who the experts are. When an expert uses his knowledge to make an educated guess there is a probability judgment. Value judgements, the results of our upbringing, are not always appropriate in decision making. By presenting scientific facts concerning drugs and their effects and the psychological and physical consequences of drug use along with the reasons for non-medical use of drugs and the social consequences of chronic drug use, the authors hope the reader will be able to evaluate the facts and be in a position to help their governments make informed decisions about drug policies. 306 references.