Um I dont think you can give a ~3 week old baby~ catnip tea... But catnip tea is safe for you, and will put you to sleep easier, but ask your doctor when you can start giving your baby catnip tea, since im guessing it would be fine once the baby is old enough to drink juice and stuff, but im not sure, so you need to ask your doctor, but ~do not~ I really mean, ~do not!~ give a 3 week old baby catnip tea! I do not believe that is safe at all!