Japanese mint oil has a good property that it contains a large quantity of menthol, but it has been expressed that it has the most weak point, which possesses a special disagreable odor. For the purposes of studying the odor of Japanese mint oil, we reported that the volatile water of "San-Bi" (M. arvensis) shall be contain ammonia, trimethylamine, dimethylamine, and monomethylamine as the nitrogen compounds, by the use of paper chromatography. The same writers reported also that the bad odor of the dementholized oil of Japanese mint can be removed by the treatment with phosphoric acid most effectively.
It has not been reported that mint plants possess amines, but only one possessed monomethylamine in M. aquatica.
As the results of studying the nitrogen compounds in the volatile waters of the several mint plants, the authors confirmed that a large quantity of ammonia and a small quantity of trimethylamine exist in them.
In regard to the existence of the nitrogen compounds in the plants, it was reported already. For the existence of a large quantity of ammonia in the volatile water, it can be assumed that this ammonia was liberated mainly by the hydrolysis of the amides.