Diatomaceous Earth or DE is an abrasive dust made from the fossilized skeletal remains of a single celled algae which used silica found in water to create a shell. It works because the microscopic shells have sharp projections that penetrate an insect's cuticle, allowing vital liquids to leak out. DE also absorbs the waxy coatings on insects' bodies both actions cause pests to die of dehydration. It works by physical rather than chemical action and is non toxic. This works on all bugs, good and bad, from cockroaches and scorpions to glass spiders and is safe to use around the house, in the garden or around pets and livestock.
To use around the house sprinkle it liberally in areas prone to infestation or where you notice you are getting bit. We put it behind our stove and under and around our fridge as well as under our couch cushions after we noticed we were getting bit, problem solved. The easiest way I have found to apply it is to buy a salt shaker or herb shaker ( we reused an old one) with small holes or you can by a bottle used to refill construction chalk lines, these can be found at hardware stores or the tool section at Walmart. If you are putting it somewhere that it will be easily blown away try adding a small amount of water to the area before you apply the DE.
Not only can it be used for pest control in the home but also for food storage and gardening. To use DE in food storage add 1-1/4 C DE to each five gallon bucket of food. Then shake and roll (the boys love this part) the 5 gallon bucket thoroughly. Obviously you only want to use this on food items that you can wash. Do not use with things such as salt and sugar. DE has no shelf life and never degrades. It will even kill insects that hatch years later. To use in the garden dust the soil or make it into a solution to spray on fruits and vegetables which protects them from insects.
I love this stuff and highly recommend you have some on hand. Although it is not dangerous the dust can irritate your lungs and cause your hands to dry out mildly so you still need to be mindful when using it. It can be found on the internet or at many grain, tack and pet food stores as it is usually fed to livestock to kill intestinal parasites. I've found it as cheap as 50lbs for $25 so not only does it work well but it is also available to those of us on a frugal budget.