Studies have shown that infused particles lead to numerous complications such as inflammation or organ dysfunctions in critically ill children. Nevertheless, there is very little data available to evaluate the amount of particulate matter potentially administered to patients, and none with regard to infants. We have investigated the quantity received by these patients during multidrug IV therapies. Two different protocols commonly used in our neonatal intensive care unit (NICU) to manage excessively preterm infants were reproduced in the laboratory and directly connected to a dynamic particle analyser. The particulate matter of infused therapies was measured over 24 h, so that both overall particulate contamination and particle sizes could be determined. No visible particles were observed during drug infusions. Particulate analyses showed a significant number of particles that can reach 85,000 per day, with peaks during discontinuous drug infusions. Moreover, we showed that very large particles of about 60 µm were infused to infants. This study showed that despite very low infusion flow rates, infants may receive a large number of particles during drug infusion, especially in NICUs. Particulate contamination of IV fluids is not without consequences for fragile infants. Preventive solutions could be effective, such as the use of in-line filters.