The sudden reddening of the malodorous fluid after the first full month is mostly considered to be caused by residues in the uterine cavity, poor recovery of the incision after cesarean section, infection and other reasons, but also does not exclude the possibility of menstruation, you need to go to the hospital for examination to clarify the cause and then deal with the symptoms. 1, menstrual flow: if the malodorous fluid suddenly turns red, there is no other discomfort, and the ultrasound examination also indicates that the uterine cavity does not see abnormalities, it is mostly considered to be caused by menstrual flow, generally no special treatment is needed. 2, residual in the uterine cavity: if there is placenta or fetal membrane residue in the uterine cavity, it will lead to infection and bleeding, so it is recommended to perform uterine evacuation under ultrasound to avoid infection in the uterine cavity caused by embryonic residue and aggravate the bleeding symptoms; 3, poor wound recovery: after caesarean section, if the healed endometrial trauma occurs in the process of suture absorption, it will also cause bleeding, which usually lasts 7-10 days. If the amount of malodorous fluid is significantly less than the amount of menstruation, and if there is no abnormal smell of malodorous fluid and no fever or abdominal pain, the treatment can be conservatively observed. If it is accompanied by fever and abdominal pain, you need to go to the hospital for examination and follow medical advice to stop bleeding, such as the use of vitamin K. 4. Infection: If improper care and bacterial infection in the body can cause the placenta to bleed again on the abruptive surface and the malodor suddenly turns red, you need to follow medical advice to anti-infection treatment, such as the use of penicillin, cephalosporins, etc. Note: The mother needs to pay attention to more rest, a light diet, less spicy and stimulating food, within 2 months after childbirth need to pay attention to warmth, avoid cold stimulation, pay attention to cleanliness and hygiene, avoid bacterial and viral infections.