Various plant-derived transient receptor potential (TRP) channel agonists such as capsaicin, menthol and allyl isothiocyanate inhibit fast-conducting and voltage-gated Na⁺-channel blocker tetrodotoxin sensitive compound action potentials (CAPs) in nerve fibers without TRP channel activation. Opioids such as morphine, ethylmorphine and codeine depress CAPs in a manner dependent on their chemical structures. Similar CAP inhibition is seen between tramadol and mono-O-demethyl tramadol and also among various adrenoceptor agonists including dexmedetomidine. We have previously reported that CAPs are inhibited by several aroma-oil compounds. The present study examined a detail of a relationship between CAP inhibitions by aroma-oil compounds and their chemical structures by applying the air-gap method to the frog sciatic nerve. Lavender-oil compounds, linalyl acetate and linalool, reduced CAP peak amplitudes with the half-maximal inhibitory concentration (IC₅₀) values of 0.49 mM and 1.65 mM, respectively. Citral, citronellal, L-bornyl acetate and rose oxide reduced CAP peak amplitudes with the IC₅₀ values of 0.48 mM, 0.50 mM, 0.65 mM and 2.0 mM, respectively, while myrcene at a high concentration such as 5 mM hardly reduced CAP peak amplitudes. Camphor at a concentration of 5 mM reduced CAP peak amplitudes by 30 %. Taking into consideration previously-obtained results, an efficacy sequence of aroma-oil compounds for CAP inhibitions was phenols (carvacrol, thymol and eugenol) ≥ aldehydes (citral and citronellal) ≥ esters (linaryl acetate and L-bornyl acetate) > alcohols (menthol and linalool) > oxides (cineole and rose oxide) >> hydrocarbons (limonene and myrcene). These results further confirmed that there is a relationship between nerve conduction inhibitions by aroma-oil compounds and their chemical structures.