The aim of this study was to examine the effect of olfactory stimulation mixed carbonated water swallow on activation of the suprahyoid muscle in healthy adults. Twenty healthy adults measured the activation of the suprahyoid muscle using surface electromyography (sEMG) when swallowing. There are the four swallowing tasks for the subjects: (1) odorless olfactory stimulation with distilled water, (2) odorless olfactory stimulation with carbonated water, (3) Black Pepper Oil (BPO) olfactory stimulation with distilled water, (4) BPO olfactory stimulation with carbonated water swallowing. Counterbalancing was done to exclude order effect. Six times for each task, total 24 times swallowing was done. 5 minute break time was given between each task, one researcher proceeded the experiment for consistency. Fix the reference voluntary contraction as 5 ml water swallowing to standardize the size of sEMG signal. Standardized data were used in statistical analysis, and statistical analyst was blind to the experiment. Among the four tasks, tasks 2 and 4 showed significantly stronger the suprahyoid muscle activity than tasks 1 and 3 in the maximum value (p<.05). In conclusion, Carbonated water, as immediate effect, could promote the maximum activation of the suprahyoid muscle, the immediate effect could not be found with BPO olfactory stimulation.