Side effects from a standard dosage of vitamin C can include heartburn, stomach cramps, nausea, vomiting, headache and others, according to WebMD. High daily doses of vitamin C may cause numerous side effects, including severe diarrhea and kidney stones.
Additional possible side effects from standard doses of vitamin C include gut blockage, chest pain, urinary complications, inflamed esophagus and dental erosion, according to Mayo Clinic. Additional possible side effects from very high doses of vitamin C include red-blood-cell destruction, pro-oxidant effects, blood clotting, digestive system complications and heart-related death.
Vitamin C is generally safe for most individuals when taken in recommended doses, according to WebMD. The likelihood of side effects increases with the amount of vitamin C taken.
Individuals with blood sugar concerns should be cautious with the use of vitamin C, according to Mayo Clinic. Caution in vitamin C use should also be taken by individuals who have bleeding disorders, high blood pressure, gut disorders, cancer or kidney stones. Those who have recently undergone angioplasty should use vitamin C with caution. Caution should be implemented for individuals taking anticancer agents, iron supplements, estrogens, HIV medications, antibiotics and some other medications.
High doses of vitamin C should be avoided in individuals with conditions worsened by increased acid, according to Mayo Clinic. High doses should also be avoided in those with kidney failure or taking potentially kidney-damaging agents.