Mortein Fast Knockdown Fly & Mosquito Killer Low Allergenic has been carefully formulated to kill insects fast while being less likely to cause sensitive reactions associated with some insect sprays. The low allergenic spray means you can use this product with confidence around your home. - Kills flying insects in 1 spray. - Low allergenic. Over 90% natural ingredients. 0.24% synthetic actives. Mortein Fast Knockdown Fly & Mosquito Killer Low Allergenic has been carefully formulated to kill insects fast while being less likely to cause sensitive reactions associated with some insect sprays. The low allergenic spray means you can use this product with confidence around your home Kills flying insects in 1 spray. Over 90% natural ingredients.0.24% synthetic actives. The low allergenic spray means you can use this product with confidence around your home.