* Isolation of ephedrine from Ephedra vulgaris in 1885. Nagai recognized it to be the active component of the plant.
* Synthesis of methamphetamine from ephedrine in 1893.  Methamphetamine was later synthesized in crystalline form in 1919 by Akira Ogata.
* Isolation of rotenone from Derris elliptica in 1902. Nagayoshi named the substance after the Japanese name for the plant, roten.
* Synthesis and structural elucidation of ephedrine in 1929.