rationalskepticism.org

In theory it works. Just always bet enough that if you win, you get all of your money back plus a small profit. But that's why casinos have maximum bets. And as soon as you hit the maximum, the strategy no longer works. It's basically like asking your friend to go double or quits until you win. How many times are they going to agree to it before they see what you're doing and tell you to take a hike?

I don't know the maths of it, but I'd imagine it's not a strategy that leads to a huge profit either, so if you had the sort of money that would allow you to do it, there are probably better ways of making it pay out.