Methamphetamine is an illegal drug which is commonly abused in Japan. Simon and Marquis tests are used for checking the presence of methamphetamine in a sample. Recently, a new fake mixture that gives positive results for both color tests has been encountered. GC-MS measurement revealed that this mixture contained 2-phenethylamine and N-isopropylbenzylamine but not methamphetamine. We applied a color test with acetone and sodium nitroprusside which showed a positive result for 2-phenethylamine and no methamphetamine. This test along with the usual Simon and Marquis tests would be useful for the distinction of this mixture from methamphetamine.