Abstract: The limit test for arsenic based on Gutzeit's test was reinvestigated. A method was chosen for the destruction of organic matters' using calcium hydroxide of low arsenic content. It has been found that the arsenic content in certain drugs such as citric acid and others may be determined without destruction of organic matters, while bromine treatment in acid solution may be required for glucose and calcium gluconate. Sulphathiazole and succinylsulphathiazole are treated with bromine after destruction of organic matters by the lime method. Certain sodium salts are treated with anhydrous sodium carbonate to remove organic interference. Iron salts may be removed by distillation with an apparatus designed by the present authors. Detailed procedures have been suggested for the drugs described in the forthcoming edition of the Pharmacopoeia Sinica.