Used for staining of nuclear DNA in specimens such as smears, prints, liquid-based samples, punctures and paraffin sections. The DNA of cell nucleus is blue or blue-violet, and the cytoplasm is red after staining with eosin. 5N hydrochloric acid solution, magnetic stirrer, etc. need to be provided, the staining solution needs to be fully dissolved, and should be ready to use, not recommended for repeated use.