Summarize this article:

When someone puts you down, deal with it by not immediately reacting to him. Giving a quick comeback or getting angry will reinforce his behavior. It gives him what he wants — a response from you.. Also, it's not good for you to act out of anger or other negative emotions. You could do or say something you will regret, or you could damage yourself with stress.   Take a deep breath or two. This will help you to remain calm. Slowly count to five while you make sure you are calm. You may want to respond with a put-down of your own, but doing this can make you seem as petty as her. It can also increase the tension, and really won't solve the problem.  Just like reacting immediately, retaliating gives her what she wants. Even though you might want to, don't reply to rude comments and posts online with mean posts of your own. Avoid gossiping about her later. It may feel good in the moment, but does nothing to solve the problem. Sometimes silence can be the best weapon. Ignoring someone that is putting you down denies them the pleasure of a response from you.  It keeps you from wasting time and energy on someone that isn't worth it. Plus, her bad behavior will really stand out against your good behavior.  Just act as though she didn't say anything. Continue doing what you were doing without giving her a glance. Unless the person is incredibly thick-headed, she will usually leave you alone after being ignored. This is a clear way to let the person know that you want him to quit putting you down. If ignoring the person didn't work or if the situation is especially annoying or hurtful, telling him to stop can help resolve the problem.  Make sure you are calm. Look him in the eyes and use a controlled, confident, clear voice. For example, if a peer insults you, take a few deep breaths and then calmly say, “Stop putting me down.” With a co-worker, you might try saying, “I don't like or appreciate how you are talking to me and about me. I want you to stop putting me down.” If it's a friend that may not actually be trying to be mean, you might say, “I know you didn't mean to, but what you said hurt my feelings. Please don't put me down like that.”

Summary:
Avoid reacting immediately. Don't retaliate. Ignore it. Tell the person to stop.