Breast self-examination actually has the best time, the best time is at the end of each menstrual period for one week, at this time the examination is more accurate, as follows: 1, visual diagnosis: one week after the end of menstruation, in the shower in front of a mirror to illuminate the upper half of the body, hold up both hands and carefully observe the bilateral nipples whether the level of the same, whether there is no ulceration of the nipple, the nipple skin is not concave, as well as the nipple has no retracted or high lifting, the nipple is whether there is an overflow of abnormalities, etc.; 2. Palpation: Raise the left upper limb, use the belly of the index, middle and ring fingers of the right hand to move slowly, steadily and carefully in the left breast in the downward or reverse direction, and gradually touch the nipple from the periphery of the breast, and finally squeeze the nipple gently with the thumb and forefinger to see if there is any nipple discharge, and if turbid, yellowish or bloody overflow is found, then immediately consult a doctor for the condition. Lying down examination, the self-examiner lying down, lifting the right upper limb over the head on the pillow, so that the breast is flat, the left hand index finger, middle finger, ring finger fingertips slowly, steadily and carefully in the left breast to do the gradual movement in the direction of the smooth or reverse, touching from the periphery of the breast to the nipple, and finally squeeze the nipple, to see if there is any discharge of fluid.