I know this is an older post, but I wanted to respond in case others are searching for this topic in the future. I had an allergic reaction to kefir, but I also suffer from a terrible leaky gut. I drank homemade, organic milk kefir regularly for a week, 1 cup per day. After about day 5, I started getting dizzy when I drank it. So I took a few days off. When I started back again, a few hours later I had a rash all over my face and my back was covered in tiny red dots. I’m going to try the store bought kind to see if I can tolerate that. Store bought is less beneficial, but I’m sure it’s better than nothing.