Asahina stayed at the university to research the chemical principles of Chinese traditional medicine under Junichiro Shimoyama.

[2] He had trouble identifying the lichens he wished to research, as at the time, Atsushi Yasuda was the only lichenologist in Japan.

Asahina developed a method of thalline color reaction and the microcrystal test of lichen metabolites.

He also studied many other genera in Japan, most notably Alectoria, Anzia, Cetraria, Lobaria, Parmelia, Ramalina, and Usnea.

[5] Asahina was awarded the Imperial Prize of the Japan Academy in 1923 for his contribution to research on Chinese drug principles.