The pharmaceutical substances are meant to exert their pharmacological effect after they bond to the human organism’s receptors, but after metabolization they reach the environment and interact with other living organisms as well. Although the concentrations detected in the different compartments of the environment are quite low (a few μg/l), as the pharmaceutical substances do not act alone, but in mixtures, their pharmacological and toxicological effects are summed. Sources of pollution are the living organisms, the agriculture and the healthcare units. The following type of compounds can be considered pharmaceutical contaminants: unmetabolized pharmaceutical substances, metabolites, conjugated forms, degradation products, solvents, raw materials and intermediates of the pharmaceutical industry. These substances reach the environment where they are in a continuous movement and interaction. Their physical – chemical properties, the capacity of adsorption and the uptake properties of the environment condition their transport and distribution.