Our pedi suggests pear or prune juice (it was before she was on solids, so juice was suggested). She said prune is best, but sometimes they won't take it, so try and disguise it with pear or just do pear. We did pear (1 oz) and had nothing, so a few hours later, per pedi, we did 2 oz prune. Umm, wow!
Re: Pear juice for pooping
We used an ounce of prune juice. My pedi said that pears only help with constipation if you eat the skin, so I am not sure pear juice would help.
We never had the problem with constipation till DD started cereal - and we'd mix about an ounce of pear juice with cereal.
But I do guarantee pear juice does work - there must be something in there other than the skin.
Good Luck!