I KNOW I've seen books recommended here before but I can't recall where or when. Maybe Wise Woman Herbals or similar title?
My ds has yowled for 2 days and it finally dawned on me to give him a warm cup of peppermint tea. 15 mins. later he had a huge "toot" and is now blissfully (and quietly) playing w/the dog collars (fav. toy). Makes me realize I need to be more aware and proactive here.