How much prune juice can be consumed per day when NOT constipated?

4 ounces a day and you can increase it to 4ounces twice a day. You may be having beginning symptoms of irritable bowell syndrome. If this pattern continues you need to see your Dr, there are medications you can take for this. It is hard to believe that the amount of prune juice you consumed would cause you to have diarrhea. RN for 30+ years and I also have IBS.