Drinking a lot is NOT a good idea ever, really, but especially not when breastfeeding. However, one is okay, and particularly Guinness for boosting milk production. It's controversial around here, but I tend to think the reason for that is that Americans are so uptight about alcohol. Go to Australia or Europe, your doctor will tell you to go drink a beer, have a banana, and relax. Of course, there are other factors involved in upping milk production. Drinking plenty of water, and nursing often. Also, I find that lifting my boob up to feel where the most milk is (you can feel the ducts that are swollen), and massaging around there helps him get more, as well as eases pain on my nipples because his sucking is more effective (rather than thinking me a big binky). It's not easy, but it is important. Good Luck!