Intravenous therapy (IT) has become an indispensable resource when there is need for infusion of large volumes of solutions, obtaining rapid pharmacological effect, administration of hypertonic substances or extremes of pH, or for administration of drugs which may be poorly absorbed by gastrointestinal tract. Thus, this study aims to analyze the pattern of IBT performed by the intravascular device through the identification of potential and pH flebitogênico major drugs administered pharmacologic therapy and to correlate the occurrence of faults infusion (phlebitis and infiltration / extravasation). This is an exploratory, descriptive study, quantitative data. The study sample consisted of nineteen children admitted to the pediatric unit of a university hospital located in Niterói, in the period November 2006 to April 2007. Data analysis was performed by means of statistics, and the results are then discussed according to the literature and considered statistically significant when p <0,05. In this sample, 93% of children made use of antimicrobials. The oxacillin was the most commonly used drug. It follows that all children had phlebitis during hospitalization. It is believed that the main factors that predispose to the occurrence of phlebitis were: dilution and inadequate administration of medications and use the same peripheral venous access for infusion of more than one medication with potential flebitogênico. Given the above, urges the incorporation of items reconstitution, dilution and infusion time on the practice of preparing and administering medication.