There are a few unpleasant plum juice side effects. Plum juice is very high in fiber and the body needs time to become adjusted to so much fiber. Therefore, it is indeed possible to drink too much plum juice. When it comes to any fruit juice, moderation is the key to reaping the most health benefits from the juice. One eight ounce glass of plum juice each morning will aid in constipation. However, any more than that could cause stomach cramping, diarrhea and irritated bowels.

Plum juice side effects are not limited to abdominal pain. Overindulging in plum juice will lead to possible weight gain. Plum juice, like all other fruit juices, is quite high in calories. If one is trying to lose weight or moderate their calorie intake, indulging in too many ounces of fruit juice will be counterproductive. It is best to limit plum juice, and all other fruit juices, to one glass a day.