Cockroaches tend to infest kitchens and bathrooms because they need access to food and water. Cockroaches cannot survive without water but the food is something they have ready access to as they can feed on things like the glue on a cardboard box. What they need constantly is water which is why they infest drains and bathrooms where there is no food. Dealing with this cockroach infestation is generally dealing in the kitchen and bathroom. There are many options including domestic and commercial treatments and many different ways you can go about treating them. The best option is a three-pronged approach using insecticide dust, gel bait and permethrin. Insecticide dust is silicon dioxide, a naturally derived dust that can be mined from the earth in its raw form. It can also be made in a lab simply by bringing silicon to a very high temperature so it burns completely to ash. The natural form mined from the ground, called diatomaceous earth, is the product of million-year-old single-cell organisms that are mined out of mountains. This dust is used in many areas of life from food storage for grain, because it is safe to eat, to filtration for vaccination production. The reason it is an insecticide occurs on a microscopic level. While the dust is safe for mammalian consumption on a tiny level the particles are razor-sharp. This cannot affect large organisms like mammals but can destroy the bodies of insects with a carapace. The dust gets right into the nooks and crannies of the insect and can break off limbs and scratch the waxy layer of their carapace that keeps moisture inside of them. It works on many different insects and can desiccate them entirely. This is best placed behind cabinets and in drawers and cupboards and can also be used to powder the floor in the kitchen close to the walls.
Gel bait is the second prong of the trident, and is only effective when you keep other forms of food away from the insects. This means storing all of your food in the fridge or tightly sealed glass or metal containers. You then must get rid of everything else that cockroaches can eat. This can include anything that was derived from an organism, either a plant or animal which can include the glue on cardboard boxes, in book bindings and even wallpaper paste and wheat paste. So if you have a wallpaper house there may be no way to stop them from getting nourishment. They can eat anything that is made of glucose so clearing the house of boxes and string books in plastic bins during the treatment is effective. This bait is best placed behind large appliances, behind the toilet and sing and in corners so it does not get stepped on. The final prong of the trident is permethrin spray. This is a chemical and a pesticide but is also a natural product produced from the sap of a chrysanthemum flower. This chemical is dangerous to humans through inhalation but not through direct skin contact. It is a good idea to wash your hands after using it as it can cause a rash but will not make you sick. When using it you want to keep your arm extended out away from your face. It can be used as something called a baseboard spray which is a spray professional exterminators do at the base of the wall all around the house in areas of high activity. You can also use it to spray inside of cupboards, inside of appliances and motors as well as along the wall where it meets the counter. This approach can end a minor infestation but if it does kill everything in four weeks you need to move on to a professional treatment.