R.I.P. Fleas Extra is an aerosol containing permethrin, tetramethrin, S-methoprene and fragrance. These ingredients have no known association with triggering asthma and there are no specific precautions advised for asthma sufferers on the label for R.I.P. Fleas Extra. However it may be advisable for another person to carry out the spraying if you suffer from severe asthma or if you have previously experienced problems with aerosol sprays or any of the ingredients. Immediately after spraying, open windows and ventilate the room for at least 1 hour. Make sure all spray mist has settled and all surfaces are dry before allowing any persons to re-enter the room. Read the label before use and adhere to the safety advice.