We have used both parachoc and prune juice with DD1 when she had issues.
How long have you been giving her the prune juice? It is not an instant fix, it took about a day before it worked with DD1 and got things moving again.
The parachoc took about the same time. And the only other thing to know with the parachoc is that she can't lie down or go to sleep for about 2 hours after she has it because the paraffin (active ingredient) can be inhaled in the lungs and cause serious breathing issues. If you know about that and follow the directions though it should be fine. I tend to steer clear of it because it kind of freaks me out that for two hours she can't lie down.

