Milk accumulation during breastfeeding can produce symptoms such as abnormal redness and swelling of the breast, localized hard lumps or nodules, intense pain, and fever. If the accumulated milk is not emptied in time, when breastfeeding again, bacteria in the baby’s mouth may travel up from the cracked nipple and cause acute mastitis or even breast abscess. The accumulation of milk during breastfeeding is often associated with cracked nipples, too much milk, improper sleeping position, wrong use of breast pump, improper feeding, etc. When milk accumulation occurs, you should adjust the way and method of breastfeeding, feed the breast with the lump first, with proper massage to promote milk discharge, and wear loose and appropriate underwear to avoid squeezing the breast to prevent mastitis. In addition, if your breasts are abnormally red, swollen, painful and feverish, you may have mastitis and need to go to the hospital in time to choose the right treatment under the guidance of your doctor. You can take oral antibiotics such as penicillin and erythromycin, etc. If an abscess forms, surgical incision and drainage can be performed to drain the pus and make the inflammation dissipate as soon as possible. During the period of milk accumulation, you should pay attention to sucking milk with a breast pump in time after breastfeeding to avoid milk accumulation, washing the nipples and surrounding areas before breastfeeding to keep them clean, paying attention to a light diet, avoiding oily food, drinking more water and keeping your mood relaxed.