Dr. T's Mosquito & Gnat Scat Flying Insect Repellent contains three natural oils and no poisons. It is a non-toxic, biodegrabable product that lasts up to three weeks, according to the manufacturer. In addition, Dr. T's Mosquito & Gnat Scat Flying Insect Repellent has a pleasant odor and is a soil enhancer and turf builder. The product can treat 4,000 square feet and is not destroyed by rain.