Depends. I wouldn't call it karma but the whole idea behind it and how every choice and thought not only effects others but ourselves? Yeah without a doubt. Big picture karma as justice? Evil returns to evil? I don't know. I believe that good will win over evil at some point, just not now. In my experience good does not always win over evil, and there is no justice here.
Since that's true some of us still have to reconcile injustice somehow or those that don't get justice get stuck as victims their entire lives. It's a good way to forgive people too, it can free people from feeling like they always have to balance the scales and seek revenge.
At the same time, I don't believe that bad people get sick and good people are healthy or anything even remotely close to that, you know physical stuff.