Bleeding 40 days after delivery is late postpartum bleeding. Most of them are caused by residues in the uterine cavity, so it is necessary to consult the hospital for ultrasound to understand the situation in the uterine cavity, and if residues are found in the uterine cavity, the uterus should be cleared in time. It may also be caused by incomplete uterine regeneration. If the uterus is still large and has not returned to its normal size before pregnancy, you can promote uterine contraction with motherwort pellets or new biochemical pellets, and review it after 1 week of treatment. The bleeding may also be caused by puerperal infection, which is usually small in amount and accompanied by fishy odor or even purulent discharge, and the secretion should be taken for culture and drug sensitivity test, and the treatment should be targeted according to the results. In addition, it is necessary to exclude gestational trophoblastic disease, cervical lesion bleeding, etc.