my 5 week old son was on prosobee for a few weeks w/out problems. now he's constipated and very fussy. tried alimentum (dr's advice); it was AWFUL.; he farted all day and u could hear his stomach rumbling. tried nutramigen; no luck; same thing. (surprisingly b/c my daughter and 4 nieces ended up being on nutramigen). IM AT MY WITS END. does anyone know if good start soy may be good for him? like i said the only problem i had w/ prosobee was constipation. hopefully good start will help????