Flies have an excellent sense of smell. Studies have shown that certain flies can detect odours from up to 7km away. They can also detect odour from stains that are not visible to the naked eyes, making them highly efficient in searching for food. The presence of the following items may be the reason why flies are found around your house or premises: -Food waste or decaying food - Food stains - Ripen fruits - Sewer or drains - Feces or dead bodies of animals