Hematoxylin-eosin staining is a commonly used staining method for tissue sections. First, tissue sections are stained with hematoxylin, which stains cell nuclei a dark blue. Next, staining with eosin makes the cytoplasm and collagen fibers appear red. This staining method is widely used in the fields of pathology, histology and anatomy, allowing researchers to more clearly observe and distinguish tissue structures under the microscope, and provides basic histological information for disease diagnosis and research.