I've never heard of reactions to it. It says to give it to them for 10 days but can be given longer under certain circumstances. I'm so mad right now, I just read that it says to keep refrigerated after opening, do you have yours in the fridge? One page says keep at or below room temperature and then if you read to the end it says that it should be refrigerated once the two bottles have been mixed. I can't believe I didn't read that before.