Explanation
A person with a cast iron stomach can eat or drink anything without any ill effects.
The idiom “cast iron stomach” means ایسا شخص جو بہت کچھ کھا سکتا ہو
For Example:
You must have a cast-iron stomach if you're eating pickles with peanut butter!
Explanation
“A wild goose chase” means a foolish and hopeless search for or pursuit of something unattainable.
It refers to an endeavor that is unlikely to succeed or achieve its goal.
It often involving a lot of effort with little chance of success.