Two of the main characteristics of western societies in the last fifty years have been the medicalization of the human life and the environmental degradation. The first one has forced human being to consider medicines use related to what would be rational, reasonable and well-reasoned. The second one brought us to a new ecologist conscience. In relation to the "human social system", the effects of medication can be considered very positive as a whole, particularly those related to the amazing increase of expectative and quality of life. But, along with those unquestionable beneficial effects, medicines have also caused some negative effects for other biotic and abiotic systems, such as microbian alterations and their undesirable consequences which have involved the massive use of antibiotics in medicine and veterinary, the uncontrolled elimination of millions of doses of all kind of drugs, additives and excipients, etc., as well as atmospheric contamination and degradation of forests and deep oceans which can have been caused by investigation and production of determinated drugs. In this context Pharmacology appears as a scientific discipline that studies the research (R), development (D), production (P), and utilization (U) of drugs and medical substances in relation to the environment. From a farmaecologic perspective the drugs utilization has its development in three main contexts, all of them closely related: prescription quality, farmaceutical care, and patient's active participation in his own disease and treatment.