Making a movieclip flash/blink

Hello all,
I’m creating a game which has a healthbar. I want the health bar to blink couple of times when it goes over a certain amount or goes below a certain amount. How could I achieve this in AS3?

I have a bar, which is a movie clip. Say it is called

healthBar_mc

Is there a way to call some functions/methods which will make the movie clip blink/flash?

With much thanks,
Mike