I'm sure you can, but I've actually been looking into kefir a lot lately, & apparently, the stuff you buy in the store isn't "real" kefir. I work with a woman who makes her own, from grains- she's bringing me grains on Monday, so I can start a batch. I'm pretty psyched! So, it sort of seems like you could chug the store kefir 24/7 & not do any damage. Real kefir is slightly alcoholic, slightly laxative, & so crammed with so many probiotics it's really amazing. I have been drinking store bought for awhile now, with my probiotics, & no ill effects.