A small amount of pelvic fluid does not require treatment and is normal. Pelvic fluid is not a disease, it is just a description. It is not possible to have no fluid at all in the pelvic cavity. In truncated position it will collect in the rectal fossa of the uterus and can be observed by ultrasound. Common causes of fluid accumulation may be post-ovulatory follicular fluid, usually within 20mm; menstrual period may also be due to the backflow of menstrual blood into the pelvic cavity; the rupture of the corpus luteum of the ovary during the luteal phase, generally a small amount will be absorbed on its own, and the painful feeling in the small tummy that manifests itself will generally disappear in two or three days. If the pain persists and there is a tendency for the temperature to rise, you should actively go to the hospital to rule out the possibility of pelvic inflammatory disease, after the diagnosis of pelvic inflammatory disease, it is recommended that the regular standard treatment, you can empirically static point antibiotic treatment for a week, observe the changes in the condition, if you stop the medication may aggravate the inflammation or the formation of adhesions leading to chronic pelvic pain in the long term, serious cases cause infertility, ectopic pregnancy, pelvic inflammatory masses In serious cases, it may cause infertility, ectopic pregnancy, pelvic inflammatory mass, pelvic abscess, etc. In summary, physiological pelvic effusion does not matter and does not require treatment, but those with obvious symptoms and effusion greater than 20 mm must be treated actively with anti-inflammatory therapy, usually with broad-spectrum antibiotics empirically. Again, a small amount of pelvic fluid without accompanying symptoms does not require treatment.