The color of the fluid in the uterus depends on whether it is pathological or physiological. Physiological uterine fluid is transparent; pathological uterine fluid is yellow or blood-colored. 1. Physiological uterine fluid is transparent, usually occurs at the time of ovulation, due to hormonal changes in the body and follicular discharge of follicular fluid will also be discharged, then there may be a small amount of uterine fluid, discharged from the vagina is colorless and transparent. 2. Pathological uterine fluid is yellow or bloody, due to inflammation in the uterine cavity, endometrial lesions, prolonged menstrual period, etc., there will be uterine fluid, yellow indicates that there is a bacterial infection, bloody with a foul smell of endometrial disease, and the same color as the menstruation is most likely to be residual menstrual blood. Clinically, if you find that there is fluid in the uterine cavity, you should go to the hospital to do the relevant examination, except for the physiological fluid in the uterus during the ovulation period which does not need treatment, and all other cases need to be treated accordingly.