Pus in the breast milk is mostly yellow in color, or appears yellowish-white in color. Pus in the milk is accompanied by high fever, localized pain and redness of the mammary glands, and it should take some time before the pus develops, which is a sign of acute mastitis. Colostrum can be yellow in color, which is normal. If breast pain occurs during breastfeeding, accompanied by high fever, you should stop breastfeeding and use a breast pump to suck out the milk and discard it. You can use a breast pump to suck out the milk and then discard it. Because there is bacterial inflammation and infection of the milk, you can’t give it to your baby to drink. At the same time, you should consult a doctor in time, you can do breast ultrasound and blood tests. If it is determined to be acute mastitis, penicillin drugs should be given promptly for treatment.