I've never tried their affiliate program, so do not have any first hand experience. I looked at their website and they have not provided much information publicly. All you can do through their website is sign up for their program. However, they haven't disclosed any details on the commission structure.
I just an email to them asking for the details. Let's see if they will respond.
If you are interested to sign up for Healthkart affiliate program, follow this url - http://www.healthkart.com/affiliate