The effects of three principal constituents (sugar, spearmint, and gumbase) in chewing gum on EEG findings in 20 normal subjects were investigated. After they chewed the gumbase, theta activity decreased significantly at Fp2, O1, T3, T4, F4, P3, and Pz; alpha activity increased significantly at O1 and decreased significantly at Fp1, and beta activity increased significantly at Fp1, Fp2, O1, T3, T4, P3 and Pz. After they inhaled the spearmint, alpha activity decreased significantly at 02, F3, P4, and Fz, and beta increased significantly at 02, F3, P4, and Fz. The mean frequency of the alpha band was significantly higher than after 1 min at rest without inhalation. After the subjects chewed the gumbase with sucrose, theta activity increased at Fp2 and Fz; alpha activity increased significantly at T3; and beta activity decreased significantly at Fpl, Fp2, F4, P3, P4, Fz, and Pz. The mean frequency of the alpha band was significantly lower than after 1 min at rest without it at almost all the positions. These results suggest that the gumbase with sucrose induced relaxed concentration effects while inhalation of spearmint induced arousal effects. The chewing of gumbase showed arousal tendency.