Drainage from the belly button scar after tummy tuck or abdominoplasty can range from a minor nuisance to a serious problem. If this problem presents immedialtely after surgery, it can be a normal occurrence. If it continues several weeks to months after surgery, it can be a sign of a retained suture that has become infected. Removal of the suture, local care and oral antibiotics can resolve this problem. Greenish color can also be a sign of a particular type of bacterial infection and should be investigated with a culture to be certain the correct antibiotic is chosen. In other instances, the superfical belly button skin or epidermis can become trapped below the skin surface. This layer of skin sheds itself routinely every week, as a result it can develop into a cyst or sinus that drains mal-odorous material. I would suggest seeking consultation to determine the cause of your belly button draiange. Best wishes.