Cockroaches are replusive and objectionable to most people simply by their presence.
They are also capable of mechanically transmitting disease organisms such as the bacteria which cause food poisoning. Recently, cockroaches have been found to be an important source of allergy in people, second only to house dust. The German cockroach is by far the most common roach found in homes. Oriental and American cockroaches usually prefer dark, damp areas such as basements, floor drains, crawl spaces, and utility closets. Cockroaches typically become established in homes after being introduced in grocery bags, with laundry or, in some cases, wandering in from outdoors.