If one dog (s), you will sooner or later once fleas. And that in spite of various preventive measures (drop, necklace, powder ...). My experience: If the flea in the house, do not use more gentle means. As a "first aid" I use always the "Trixi-long-term vermin environment spray" a. Unlike a Fogger (nebulizer) one can determine the level of application and spraying even smaller areas. Dealing with this spray and strong poisons contained therein must however be carried out very carefully! Please read the operating instructions and adhere to exactly! I never spray to things that touch the dog. Instead, I cook his ceiling and use the spray for corners etc. can act After spraying a few hours in enclosed areas and then ventilate well. I do it always in the spring and then let open overnight the window. After such a treatment that is coming neither mosquitoes nor fly into the house. And if so, then they go into shortly. The smell is surprisingly neutral and even for sensitive noses no problem. Since fleas then vermehrenbzw in 14Tages-rhythm the larvae hatch, after this period an eventual post-treatment is necessary. Depends on the intensity of infestation. Has the dog again guests need to act immediately. Therefore, I have this spray always in the house as an effective first measure (well hidden that permethrin contained please do not underestimate !! In the US it is as easy carcinogenic HUMAN! Classed !!) also must be taken when keeping still other pets caution or the use of this spray is not recommended. PS: At this point I had fallen into my original review on a fogger. This I withdraw. Have you used and am freed after decades dog ownership, alternative funds and countless tips and tasting only of this spray of the fleas. Unfortunately. Wish myself it would be possible without chemistry club. The spray smells not sweet violets, it also makes no fun when spraying to be there - but it helps 100 per!