What can overdosing on zinc tablets do to you?

Bad things. Acute adverse effects of high zinc intake include nausea, vomiting, loss of appetite, abdominal cramps, diarrhea, and headaches. One case report cited severe nausea and vomiting within 30 minutes of ingesting 4 g of zinc gluconate. Intakes of 150–450 mg of zinc per day have been associated with low copper status, altered iron function, reduced immune function, and reduced levels of hd lipoproteins.