★★★★★
My mom always had prune juice in the house for those occasional bouts of constipation. I would image 1/4 to 1/3 of a cup would be plenty as it is very sweet.
The other thing that works like a charm is celery juice, but I find it less gentle than prune juice. You will be cleaned out, but the need to go can come on somewhat abruptly and with a vengeance.
I love this site and look for natural remedies for everything. Thank you, Earth Clinic!