Acute mastitis is an acute purulent infection of the mammary gland, which is a common and frequent disease among lactating women, most common in primiparous women, usually occurring 3-4 weeks after delivery. Mastitis during lactation has a rapid onset and changes rapidly, affecting normal breastfeeding, causing great physical discomfort and psychological stress to the mother, and in severe cases often leading to discontinuation of breastfeeding, affecting the health of both mother and child. Most of the patients have symptoms such as chills, fever and fatigue at the beginning of the disease, and most of them have high blood counts and neutrophil ratios. Treatment method Use a towel soaked in 20% magnesium sulfate solution and then apply a hot compress to the breast lump for 30 minutes each time, replace the towel after it cools down, 4-6 times a day. Apply a little petroleum jelly to the sore breast, hold up the breast with one hand, separate the 5 fingers with the other hand and massage gently from the root of the breast to the nipple with the 5 fingers from all around the breast in the direction of the nipple in a combing grip, the grip should not be squeezed or rotated and pressed with force, but in the direction of the milk ducts, apply downward pressure to slowly drain the accumulated milk, about 10 times. Then use the 2 fingers of the right hand to pull the nipple upward to extend the milk ducts in the areola area. Then hold the breast with the 4 fingers and squeeze the milk from the root of the breast to the nipple with a little force with both thumbs to make the milk drain. If the body temperature is elevated and the blood count is high, use antibiotics and antipyretics with supportive treatment. If the abscess has not formed, breastfeeding can be done normally. For abscess formation, if the abscess is small, single abscess, and the patient’s systemic toxic symptoms are not obvious, puncture and pus aspiration and intracavitary drug injection can be used for treatment. Puncture and drug injection is done once a day or every other day until it is cured. If the abscess is large or multiple, and the patient is combined with chills and high fever, the abscess should be promptly incised and drained. If the abscess cavity is large, the fingers should be separated from the fiber interval, the pus should be drained, the pus cavity should be flushed with sterile saline, oil gauze should be placed in the cavity, and the medicine should be changed daily or every other day until the abscess cavity is closed. In case of combined milk leakage, weaning should be done promptly. The two main causes of acute mastitis during lactation are lactation stasis and bacterial invasion. The common causes of milk stagnation are: (1) abnormal nipple or ducts: such as nipple entrapment or small nipple, which makes sucking difficult for the infant; a history of previous surgery may lead to adhesions of the ducts and poor milk drainage. (2) The mother lacks breastfeeding experience or the baby sucks less milk and cannot make the milk empty completely. (3) Cracked nipples, painful refusal to breastfeed, and stagnation of milk. The causes of bacterial invasion are: (1) Insufficient maternal breast care and cleaning after breastfeeding. (2) Cracked skin at the nipple and areola. (3) Infant oral co-infection. The infecting bacteria are mainly Staphylococcus aureus and Staphylococcus albus, but Staphylococcus aureus is predominant. If the person is not allergic to penicillin, penicillin treatment can be preferred. If the person is allergic to penicillin, erythromycin can be used. For the cause of the disease we have to take active preventive measures to avoid mastitis. If the nipple is sunken in, surgery should be performed before pregnancy to correct it; for less severe cases, nipple exercises can be done to improve the sunken nipple by pulling it frequently and repeatedly. For those who have severe nipple invagination or no nipple, they cannot breastfeed after delivery and should be weaned immediately after delivery. Master the correct method of breastfeeding, induce milk discharge as early as possible after delivery, and keep the milk excretion system open. Breastfeed both breasts at a time. For those who do not suckle, empty the milk as much as possible to make the breasts soft. For cracked nipples, keep the area clean and dry to promote wound healing and suspend breastfeeding if necessary, but empty the milk. During pregnancy and breastfeeding, you should often wash your breasts with warm water to keep your nipples clean, and pay attention to the oral hygiene of your baby. As you can see, the prevention of acute mastitis during breastfeeding is crucial, and we need to raise awareness to avoid the disease. Once you have mastitis, we need to diagnose and treat it as early as possible to stop the further development of the lesion. Local wet and hot compresses and lactation and drainage methods are simple, easy to master and have reliable efficacy.