Possible adverse health effects of vitamin C and ascorbic acid

Consensus from individual studies and several review articles is that consumption of supplemental vitamin C leads to no significant adverse health effects to humans in general. Individuals who have a history of kidney stone formation and those who experience iron overload should exercise caution before using supplemental vitamin C. Occasionally, individuals experience diarrhea or mild nausea. There is also the possibility that vitamin C taken simultaneously with other drugs may contribute to adverse health effects and that its interference in clinical laboratory tests will mask diagnosis of disease. Few controlled clinical trials exist that conclusively demonstrate the adverse health effects that humans may experience with supplemental vitamin C usage, and before definite conclusions can be made of the health hazards to humans, more clinical trials are required.