Why does welches g juice cause quick bowel movement and diarrhea?

hello everyone iv been drinking welches g juice for about the last 6 months for health but i noticed when i drink 16oz or more i get a bowel movement with and hour or so and sometimes i get severe diarrhea cha cha cha. you have to drink about 4 cups to get the extreme diarrhea but it lasts for hours. whats in the welches g juice that causes a fast bowel movement or diarrhea. if anyone is ever constipated or blocked up dont waste your time on a laxative go straight for the welches g juice it will unclog you very fast.