What's the harm of cooking in a rusty pot?

Rusted iron pots will produce ferrous ions necessary for human hematopoiesis when cooking without rust. Therefore, it can prevent and treat iron deficiency anemia. However, rusty iron pots will produce trivalent iron ions when cooking, which is harmful to people's liver. Cooking in a rusty iron pan for a long time will do harm to the liver. So, brush the pot clean before cooking.