<p>Accidental overdose of iron-containing products is a leading cause of fatal poisoning in children below 6 years. 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 case of Folic acid overdose has been reported. Zinc toxicity has been seen in both acute and chronic forms. Ingestion of 150 to 450 mg of zinc per day has been associated with low copper status, altered iron function, reduced immune function, and reduced levels of high-density lipoproteins. So, Zinc at its RDA dosage does not cause any significant effect.</p>