I usually just make tea for babies…works well. Catnip (also a mint) is wonderful for baby belly aches.
The entire aerial portion of the plant can be used but the leaves have the most medicine.
Remember when making tea from mints to put a lid on it. They have a lot of wonderful volatile oils that you want to keep in there. Boil the water. Turn it off. Add a teaspoon or so of dry herb/cup. Cover and let it sit. When it’s cool enough to drink, it’s ready.
Doc
Don't use herbs or combine herbs with medications or use them during lactation or pregnancy without talking with your healthcare provider.