Mucociliary transport (MCT) represents the first barrier of the nasal fossae and paranasal sinuses against various biological and physical insults. We studied the nasal MCT time using a mixture of vegetable charcoal powder and 3% saccharin in three groups of patients suffering from hypertrophy of the inferior turbinates, deviations of the nasal septum or chronic sinusitis. The mean values of the nasal MCT in the first two groups were practically identical to the normal ones. In contrast, significantly delayed times were found in patients with chronic sinusitis (P < 0.01). Findings indicate that this delay is determined by an increase in viscoelasticity of the mucus following the acute release of mediators of inflammation, together with a reduction in the periciliary stratum, which slows down the metachronous wave of the MCT.