A family of very small (about 3mm) flies, some with prominent red eyes, characterised by a slow hovering flight in which the abdomen hangs down. All are associated with rotting fruit and vegetables or fermenting liquids. One species breeds in sour milk, for example, in the residue of forgotten milk bottles.
Remove all empty bottles or cans, and check for rotting fruit, vegetables or pools of spilt liquid. A fly killer may be used to control small outbreaks in the home.