N-Nitrosopyrrolidine (NPYR) is a chemical compound that falls under the category of nitrosamines. Nitrosamines are potent carcinogens, and NPYR is no exception. It is formed when nitrites, which can be found in certain foods or used as preservatives, come into contact with secondary amines in the digestive system. NPYR has been shown to cause cancer in various animal models, particularly in the liver and pancreas. However, its carcinogenic effects in humans are still a subject of ongoing research.