In this recipe, the juice is sweetened by the pure sugars existing within the prunes combined with apple juice to form a velvety and inviting juice. For a spiced version add ground cinnamon or ground nutmeg to the prune juice. Prunes are also beneficial as a natural laxative to ease constipation, drink one cup of prune juice every day to aid digestion. Learn how to make prune juice by following these steps: