Ascorbic acid is a water-soluble vitamin and is not usually stored. Thus, there is little evidence of toxicity.
Still, many potentially harmful effects have been attributed to excessive intakes of ascorbic acid, but the frequency of recorded toxicity is quite low.
Excess ascorbic acid intakes in humans and laboratory animals have been reported to produce a variety of toxic signs or symptoms including allergic responses, oxaluria, uricosuria and interference with mixed- function oxidase systems.
Although some investigators have suggested that megadoses of ascorbic acid may be a risk factor in renal oxalate stores, urinary oxalate levels do not change with increasing intakes of ascorbate.
Ascorbic acid toxicity also found to produce rebound scurvy among infants and pregnant women.
Toxicity of ascorbic acid
