Large doses of vitamin C can cause diarrhoea

True. Diarrhoea is one of the side effects of megadoses If vitamin C, usually those in excess of one gram (1000 milligrams). It should be noted that the RDI Recommended Dietary Intake) for vitamin C in various countries varies between 30 and 60 milligrams per day. The body becomes saturated (cannot retain any more) by daily intakes of 150 milligrams. The most vitamin that can be obtained realistically from food is 500 milligrams per day, using very high content vitamin C foods, and it is unlikely that a person would sustain this level of intake.

There is no proven therapeutic use for vitamin C in loses exceeding 500 milligrams per day.