<p>Accidental overdose of iron containing products is a leading cause of fatal poisoning in children fewer than 6. Avoid higher doses if you have liver disease or hemochromatosis; excess can cause bloody diarrhea, vomiting, acidosis, darkened stools, abdominal pain. Symptoms may clear in a few hours. Riboflavin is reported to be completely safe and no toxic symptoms have been reported so far. Higher doses of Nicotinamide may cause vomiting, diarrhea. Sensory neuropathy was observed in individuals consuming more than 200 mg Pyridoxine for very long periods. No cases of Folic acid overdosages have been reported. Acute ingestion of Ascorbic acid, even of massive doses, is unlikely to cause significant effects.</p>