I've had three pregnancies and have taken all kinds of vitamins but I've NEVER had this reaction. The first time I took was right after breakfast. Within 20 minutes I had horrible pain in my upper stomach/chest area. To the point I questioned if I was having a Heart attack. I attributed it to having just had breakfast. Maybe there wasn't enough food in my stomach and having just had coffee it didn't mix well? I took again the next day thinking it was just a fluke but waited until after lunch. Same thing, burning chest pain. Maybe it was what I ate for lunch? It was a little spicy and I had just drank a seltzer water, maybe it was the carbonation. Stupidity tried again on day 3. I took it with water and had a bland lunch, full stomach, no reason to have a reaction. Again, horrible, painful feeling in my chest and stomach. I don't have stomach issues. I've never had reactions to vitamins. Read the other reviews, this is not normal