The danger of rubbing the breast hard, to clarify what the breast is composed of, it includes the skin, glands, fat and other soft tissues such as blood vessels, hard to rub the breast is to give it the role of a larger external force. If the breast is not bleeding, it will not cause any harm, although it will not have any benefit. But if there are other lesions in the breast, rubbing hard may cause adverse effects, such as breast cancer lesions in the breast, rubbing hard may promote breast cancer metastasis or spread along the bloodstream. Therefore, if there is no problem inside the breast and breast cancer is excluded, rubbing the breast hard will not cause any harm.