Understand the reason
First of all, try to find a reason for the problem. Determine whether the co-worker is doing it intentionally or it is in their nature. There are many professional jealousies between colleagues in the office and you may be a victim of one.
Talk to the person concerned
A good way to resolve the situation is to talk to the concerned person. You need to let the person know that you have nothing against him or her and try to resolve the issue in this way. Negotiating is the best possible solution to a problem you face.
Try to mind your own business
If there is no considerable result after talking, you must try to mind your own business. Ignore anything the co-worker says; just do your work and go home. Do not get yourself involved in any discussion with the person and be to-the-point.
Discuss the situation with a colleague
You can discuss the situation with a colleague whom you trust or feel is on your side. Remember, you may not be the only victim.
Talk to your boss
This should be your last resort. If the situation gets out of control, talk to your boss about it. Let the boss know how your work is being affected by the behavior of the co-worker.