Prune juice is my only solution to constipation but it gives me a watery stool. will it be bad for me to take it 3 times a week?

Constipation: For how long? Do you drink about 2.5 liters of fluids a day and eat fiber like 1 cup of oats lentils. brown rice or barley a day? Other high fiber foods include strawberries, kale. Though a BM 3 x a week is adequate though not ideal, the diarrhea associated with prune juice suggests a food intolerance which could lead to other nutritional deficiencies. R/O Ogilvie F/U w/ GI/ nutritionist