gms | German Medical Science

Introduction: Menthol (C₁₀H₂₀O) is a natural compound of plant origin. Its isomer l-menthol is the one with the characteristic peppermint odour and the effect of cooling sensation when applied to skin and mucosal surfaces. The aim of this study is to assess the effect of menthol inhalation on the subjective sensation of nasal airflow and temperature of the nasal mucosa.

Methods: Eighteen healthy subjects with a mean age of 30 years were enrolled in this study. Anterior active rhinomanometry was performed before and after inhalation of a 2 minutes suprathreshold l-menthol stimulus. All subjects completed a visual analogue scale (1–10) before and after l-menthol inhalation regarding their sensation of nasal airflow. Continuous detection of the mucosal temperature on the septum was performed at the level of nasal valve area by means of a miniaturized thermocouple.

Results: Mean mucosal temperature before menthol inhalation ranged from 27.7°C at the end of inspiration to 31.7°C at the end of expiration. After menthol inhalation the mean end-inspiratory temperature was 28.5°C reaching 32.7°C at the end of expiration. There were no statistically significant differences between the temperature values before and after inhalation of l-menthol vapours. Nasal patency assessed by rhinomanometry was not significantly altered, although the majority of the subjects (16 of 18) reported improvement in nasal breathing.

Conclusions: Although subjective improvement of nasal airflow was reported, the findings of this study do not demonstrate an impact of menthol vapours on nasal airflow. Additionally, menthol inhalation does not have an effect on end-inspiratory and end-expiratory mucosal temperature.