Administering the Sodium Monofluoracetate, SMFA, to the rat, the quantitative determination of ammonia and glutamine in the rat brain was made by the Conway's microdiffusion analysis and on the other hand amino acids by the paperchromatography. The results as follow, To wit: 1) In the convulsion stage caused by SMFA administration, ammonia content in its brain was 2.18 mg%, glutamine 63.9 m%, glutamic acid 120.7 mg%, γ-aminobutylic acid 25.2 mg% and aspartic acid 42.8 mg%. 2) About the hourly observation after the SMFA adiministration to the rat. a) Ammonia content in its brain showed gradual increase in 4 hours up to 4 times of control value. b) Glutamic acid content showed always low level in 4 hours but the lowest one in the first one hour. c) Glutamine content also decreased in all 4 hours, remarkably at the first and thlast. d) γ-amino butylic acid content decreased. e) Aspartic acid content increased remarkably in the first 10 minutes, and then decreased. But it showed remarkably increased at the 4th hour again.