There are many reasons why milk decreases after mastitis, and they are analyzed as follows:1. Damaged breast tissue, breast milk stagnation in the mastitis period, bacterial infections lead to damage to the breast tissue, scarring and difficulty in secretion of milk.2. Mental stress is too great, too much stress in life or serious mental illnesses lead to a decrease in secretion of milk. You can relax your mood and have psychological counseling if necessary.3. Reduced breastfeeding, lack of baby sucking stimulation leads to reduced milk secretion.4. Insufficient nutrition, need to supplement high protein food, such as fish, eggs, milk.5. Breast diseases, such as severe malformation of the milk ducts, resulting in the production of milk can not be discharged will aggravate the mastitis. Breast fibroid tumors can increase rapidly during breastfeeding, affecting the discharge of milk need to be surgically removed, and attention should be paid to protecting the operated area to prevent infection after surgery.