The article discusses the histochemical demonstration of acid phosphatase activity, focusing on the limitations of existing methods and the development of improved techniques. The lead sulfide method, while widely used, is criticized for its errors and artifacts, such as nonenzymic impregnation and nuclear staining. The azo dye methods, particularly those using naphthol AS derivatives and hexazonium pararosanilin, are highlighted for their superior performance due to the low solubility and high substantivity of the naphtholic hydrolysis product and the rapid coupling rate of hexazonium pararosanilin. The authors recommend the α-naphthyl phosphate-hexazonium pararosanilin technique for its precise and artifact-free localization, while the naphthol AS-TR phosphate-hexazonium pararosanilin method is suggested for tissues with high enzyme activity. The lead sulfide method is noted for its electron density but is not recommended for routine microscopic demonstration due to its artifacts. The article provides detailed protocols for preparing tissue sections, preparing stock and working solutions, and performing the staining procedures.The article discusses the histochemical demonstration of acid phosphatase activity, focusing on the limitations of existing methods and the development of improved techniques. The lead sulfide method, while widely used, is criticized for its errors and artifacts, such as nonenzymic impregnation and nuclear staining. The azo dye methods, particularly those using naphthol AS derivatives and hexazonium pararosanilin, are highlighted for their superior performance due to the low solubility and high substantivity of the naphtholic hydrolysis product and the rapid coupling rate of hexazonium pararosanilin. The authors recommend the α-naphthyl phosphate-hexazonium pararosanilin technique for its precise and artifact-free localization, while the naphthol AS-TR phosphate-hexazonium pararosanilin method is suggested for tissues with high enzyme activity. The lead sulfide method is noted for its electron density but is not recommended for routine microscopic demonstration due to its artifacts. The article provides detailed protocols for preparing tissue sections, preparing stock and working solutions, and performing the staining procedures.