is using household insecticides harmful to human ?

Answer 1

If you follow the instructions, and use common sense, they're usually not harmful to most people. Some people will be sensitive, however, and many people will get sick if you use too much. I wouldn't use them inside if there are babies or people with weak respiratory systems, and I wouldn't use them in or near the kitchen at all.

Answer 2

Insecticides are poison. It isn't a one time use that does the harm it is the build up over time. I make a solution of bleach and water and spray around the outside of the house. I don't want insecticides on my raspberries.