The answer to 'what is bed bug' is that bed bugs are small, flat insects that feed on human blood. They are about the size of an apple seed and are reddish-brown in color. Bed bugs typically hide in cracks and crevices, such as in mattresses, box springs, and bed frames, and come out at night to feed on sleeping humans.
Bed bugs are not known to spread disease, but their bites can cause itchy skin reactions and discomfort. They can be difficult to eliminate and often require professional treatment to get rid of them completely.