A method for measurement of nasal mucociliary clearance in vivo is described. A drop, containing saccharine sodium and indigo carmine is placed on the edge of the ciliary epithelium in the entrance to the nose. The time between placement and the sensing of the sweet taste as well as the appearance of a blue line in the nasopharyngeal cavity is measured and called the transport time. Two preservatives, two nasal drops and one viscosity-increasing substance have been investigated and the results are compared with their effects on the ciliary beat frequency of chicken embryo tracheas in vitro. The more the transport time is increased by a compound the more the ciliary beat frequency is decreased. Chlorbutol 0.5% increases transport time more and decreases ciliary beat frequency more than benzalkonium chloride 0.006% + EDTA 0.1%. Otrivin 0.1% increases transport time more and decreases ciliary beat frequency more than Rhinoguttae xylometazolini 0.1% (F.N.A.). These results support those obtained with the photo-electric registration device applicated on chicken embryo tracheas and human adenoids as described in earlier publications.