Abstract: In a previous article we have reported xylene cyanol (XC), one of the two dyes selected from 70 species of acid dyes for the determination of amines. These dyes possessing sulfonic acid or carboxylic acid radical have not yet been reported in the literature. This article reports erioglaucine(EG), the other best dye selected. The limits of detection of this dye for benethtropine -1,1-diphenyl-2(3-tropanyl) ethane and benactyzine (benzilic acid 2-diethylamino-ethyl ester) are 15 ng/ml and 20 ng/ml respectively. The absorption coefficients (E(1cm)^(1%)) of the EG-amine complexes are 4～6 times as high as those of bromothymol blue (BTB). Chloroform extract of the complex shows greenish blue color, λ_(max), 635.5 nm. For the determination of amines the preferable concentration of the dye used is 2 × 10^(-3) mol/L. The calibration curves are linear in the range of 0～7(I)and 0～10(Ⅱ)μg/ml. With the dye concentration of 2×10^(-3) mol/L, the mole ratio of dye-amine complex in the chloroform extract for benactyzine is EG : benactyzine=1:1, and 0.5:1 with 2×10^(-4) mol/L. But in the ease of benethtropine, the mole ratio with different dye concentration keeps constant at 1.3:1(dye:amine). The coefficients of variation for determination of 0.2 μg/ml benethtropine and benactyzine are within±5%, and±1～2% for 2.5μg/ml,5.0 μg/ml and 10.0 μg/ml. Similar to XC, this dye belongs to a new type of acid dye for the determination of amines, and the following portion is also considered to be the fundamental structure: