http://goaskalice.columbia.edu/can-alcohol...s-effectiveness

Depends on which type of pills you're on. I'm on Marvelon pills for almost a year now. Having it because of my period problems. So far, not much problem to me except sometimes, you'll get nausea in the mornings. Anyway, it depends on your body as well. Marvelon's the safest pill you can find in Malaysia. Have regular body check if you're that worried.