The objective of this study was to prospectively find the normal values of smell detection threshold
(SDT) in Thai adults using glass sniff bottle technique. The authors studied 131 healthy Thai adults (65 male
and 66 female, aged 20 to 60 years, median 26 years). In this test, different concentrations of phenyl ethyl
alcohol (PEA) were applied according to a pre-established order. The SDT values were estimated using a 7-
reversal initially ascending single staircase procedure and presented as log values of lowest concentration of
PEA that could be detected. The results of the present study showed that the median value of SDT in Thais was
-12.3 and both male and female were equally -12.3. The value from the present study can be used as a standard
reference for patients who have olfaction problems both in routine clinical practice and in research study.

Keywords: Olfaction disorders, Phenyl ethyl alcohol, Sensory thresholds, Smell