In this article I am going to talk about a burning social curse, the drug addiction. Dependence on a substance (drug addiction) is a set of symptoms suggest that an individual continues the use of a substance despite the problems of toxicity. Tolerance and dependence physics are included under this definition, but they are not sufficient, alone, to warrant a diagnosis of drug addiction, for which is required of the combination of at least 3 symptoms. The variables which may influence the odds that a common individual could become a consumer or worse, a drug addict are related to the his social and affective surrounding, his interior and intimate sphere, his economic position, his cultural heritage…There are also genetic basis which could contribute to the arising of drug addiction, and it is above all our biological constitution that dictate the reaction of the organism due to the drugs, the type of addiction, the effects of abstinence…We wrongly make difference among “soft drugs” such as marijuana, hashish or opium, and “heavy drugs” like cocaine, heroin or ecstasy, because they both determine devastating consequences in the long-term, that drug consumers almost never consider. It exist so many chemical mixes of psychoactive elements which produce loss of ability to react to stimulus, incapacity to assess and monitor actions, lack of personality, mental changes, distorted perception of space and time, and alteration of all the basic functions. On the organism, the drug is able to cause irreversible damage to several organs, particularly on cerebral, respiratory, reproductive systems and it’s not enough…in some cases, tumors or similar pathologies cannot be excluded. We have the moral and human duty to stay close to addict people, to prevent this horrible phenomenon, to be informed and sensitive, especially young people need to be preserved from this awful monster also through the work of police forces and institutions, if even the best mean of defence is our little but decisive, daily contribution.