I can’t speak to herbs, but our baby was projectile vomiting a lot, and it was food allergies from what Mama was eating. Once she cut out milk, chocolate and wheat (poor lady), there was no more vomiting.Kellymom.com has some good articles about food allergies. Cruciferous vegetables can also be a big trigger. Not sure if that’s the deal here but just sharing our experience. It was a dramatic change for us after a few days of avoidance.