acne
"I was on Yaz for about a year. It cleared up my severe acne almost instantaneously (though I actually broke-out severely in the very beginning). I also noticed a  decreased growth of facial/body hair. My periods were also much shorter and I had much lighter flows. The only negative side effect that I noticed was slight weight gain. I have been off the pill for a few months now, because my insurance no longer covers it at all."