Hello, Thanks for writing to us. If you are sexually active, then dark brown discharge (like chocolate) for long time needs to be concerned. Implantation bleeding should be ruled out. I suggest you to undergo one blood test for beta-hCG and Trans Vaginal ultrasound scan to rule out underlying pathology or product of conception. Other reasons are endometriosis, old blood, endometrial tissue, hormonal imbalance, stress/ depression, vaginal/ pelvic infection etc. Please consult with gynecologist for complete health check up with relevant investigation. Take proper medication if required. Maintain genital hygiene. Avoid mental stress. Practice safe sex in future. Good luck.