Cold Turkey Decided Stop Drugs Loop Abruptly Gradually

1. Harry decided to stop smoking cigarettes all at once. He decided to quit cold turkey.
2. Many doctors believe that if you want to give up using a drug, you can’t do it gradually. You have to stop cold turkey.

This slang expression was originally used to describe a way of stopping the intake of addictive drugs, and is still used most often in reference to drugs, including cigarettes.