Where does stinky smell come from?

Stinky smells typically come from the breakdown of organic matter, which can involve bacteria, fungi, and other microorganisms. These organisms decompose substances like food, waste, or dead plants and animals, releasing volatile organic compounds and gases such as hydrogen sulfide and ammonia, which are responsible for unpleasant odors. Additionally, certain foods, chemicals, and even some bodily functions can also produce strong smells.