Hi, Thanks for writing to HCM. I understand your concern. Kelnor contains 2 hormones - a progestin and an estrogen. This combination hormone medication is used to prevent pregnancy. Besides preventing pregnancy, pills may make your periods more regular, decrease blood loss and painful periods, decrease your risk of ovarian cysts, and also treat acne. Commonly encountered side effects include: Nausea, vomiting, headache, bloating, breast tenderness, swelling of the ankles/feet due to fluid retention, weight change, vaginal bleeding between periods (spotting) or missed/irregular periods may occur, especially during the first few months of use. But since you are complaining that you are having dark brown bleeding and clots, it is quite unusual and needs to be evaluated. Tell your doctor right away if you have any other side effects like unusual changes in vaginal bleeding. Kindly consult Gynecologist in this regard for proper evaluation and management. Hope th information provided would be useful. All the best.