If you dream that you are bulimic (you binge and purge), most often this signifies a true-life eating disorder that you may have. But if you eat healthfully in your waking life, then this dream signifies your need of more love and friendship in your real life. This dream might also suggest that you have not treated a friend as well as you should have.
If you dream of a friend being bulimic, again this could signify an actual eating disorder they have.
If you’re sure that’s not the case, then it could mean your friend is crying out for more attention and affection.... My Dream Interpretation
Dreams of constipation symbolize that you’ve been suppressing your power, holding back your creative impulses and keeping a back log of negative energy. Perhaps you’ve being stuck in unworkable patterns, and your subconscious mind is giving you the message to vent daily, to become regular with your emotional purges.... Strangest Dream Explanations