Pyrethrins have been called the perfect insecticide based upon its many features.  Pyrethrins are effective on a broad range of insects and yet present a very low risk to humans and pets when used around the home.  Pyrethrins are a contact insecticide and repel or kill insects that are present, but degrade rapidly in the environment leaving no residue after several hours.  Since Pyrethrins are extracted from Chrysanthemum flowers, it is a sustainable product that fits well into "green products".