Bed bugs feed mainly on the blood of humans, but also suck blood from other animals, birds and bats. Bed bugs usually feed at night when people are asleep. As they feed, they inject a salivary secretion into the wound to prevent coagulation. This fluid often causes the skin to itch and become swollen. Bedbug bites are extremley irritating.

Scratching causes sores which may become infected. Bed bugs are not known to transmit human pathogens, including hepatitis B and HIV.

The adult bed bug is brown, ovoid in shape, and has no wings. It is about 5mm long. The newly hatched bugs are almost colourless and similar to the adult except they are much smaller. When full of blood, the body becomes swollen and the colour changes to dark red.

During the day, bed bugs hide in skirting boards, cracks in the walls, bed headboards, around bed base and mattress and in the bedding. Bed bugs are carried into homes in clothes, second hand beds and bedding, furniture, suitcases, or by other people.