Epidemiological studies have shown that vitamin or trace-element deficiencies are frequent in the general population. Food intake can be incriminated, but various drugs may also precipitate micronutrient deficits. Indeed, the consequences of pharmacotherapy on micronutrients are yet modestly explored in clinical practice settings. We aim at sensitizing physicians on the impact of frequently used drugs on vitamins and trace-elements. High risk populations for micronutrient deficiencies and indications for substitution are discussed.