- INTRODUCTION: Aerosol therapy in infants may be greatly compromised by face mask rejection due to squirming and crying. Lung aerosol deposition in crying infants may thereby be greatly reduced. Since 'suckling' on a pacifier calms infants, they should more readily accept a face mask that incorporates a pacifier. However, since infants must breathe nasally while suckling, lung aerosol deposition may be reduced due to impaction in the nose. The aim of the present pilot study was to compare lung aerosol deposition while suckling on a pacifier incorporated into a mask with that obtained while inhaling from a conventional mask. METHODS: Twelve infants <12 months old and who regularly used pacifiers participated as their own controls. Lung aerosol deposition was measured scintigraphically (technetium-(99m)DTPA-labelled normal saline aerosol, MMAD (Mass Median Aerodynamic Diameter) 3 um and GSD (Geometric Standard Deviation) of 2) via jet nebuliser using a conventional mask versus 'suckling' on their pacifier incorporated into a unique mask. RESULTS: Mean lung deposition (± SD) while suckling using a mask with attached pacifier (1.6 ± 0.5% in the right lung) was similar to that with a conventional mask (1.7 ± 0.9%, p=0.81). CONCLUSIONS: Lung aerosol deposition during nasal breathing while suckling on a pacifier-equipped mask is similar to that in infants breathing quietly using a conventional mask, and results comparable with previous data in infants and in nasal breathing models of an infant's upper respiratory tract. Using a pacifier during aerosol treatment in infants may be as efficient as conventional treatment without a pacifier.