35 normal tension glaucoma patients were followed during 8 to 11 month. 12 patients received 2 x 200 mg/day Naftidrofuryl, a serotonine S2 receptor antagonist. As controles, another 23 patients were followed without treatment. The treated group, compared with the 23 non treated patients showed a significant increase in visual acuity (p = 0.001), a significant increase of the MS (p = 0.03), and a non significant decrease of the MD and CLV on the Octopus visual field (p, NS). The physiology and physiopathology of serotonine and S2 receptor antagonist are discussed.