yes can but don't apply directly. take a very small amount on your palm, rub your palms together and then on baby's tummy. do a patch test first as some babies are allergic to ruyi oil. i'm using minyak telon which is safe and very good for babies. minyak telon is very well-known and effective too.
i am also using telon cream not ruyi but also not too much as my bb skin is very sensitive