Iron Stomach 

Having a stomach that can handle spoiled food or drink and not be affected by it

Joe ate some pizza this morning from several nights ago that was left out, and on top that he also ate some cereal with spoiled milk and did not get sick, he has an iron stomach

Iron Stomach by kickerfx4 March 8, 2009

Iron-Stomach 

When someone mixes vodka and cider and proceeds to drink it.

Tim over there has a iron-stomach after mixing vodka and cider and drinking it.

Iron-Stomach by Le Buck December 2, 2019