It is the most common of all domestic flies, accounting for about 91% of all flies in human habitations, and indeed one of the most widely distributed insects, found all over the world; it is considered a pest that can carry serious diseases.

Bottle Flies also known as blow flies are usually the first insects to come in contact with carrion because they have the ability to smell dead animal matter from up to 1 mile away. Upon reaching the carrion, females deposit anything up to 500 eggs onto the body.

Large numbers of blow flies in your house usually means there is a dead mammal lurking somewhere i.e a dead rat under the floorboards.

Unlike more familiar blowflies such as the bluebottle, cluster flies do not represent a significant health hazard because they do not lay eggs in human food. However, the flies are a nuisance because when the adults emerge in the late summer or autumn they enter houses to hibernate, often in large numbers and are difficult to eradicate because they favour inaccessible spaces such as roof and wall cavities. They are often seen on windows of little-used rooms hence their other name, attic flies.