Our drain fly repellent uses Citronella, a plant-based fly repellent. This drain treatment is safe for your home, hotels, bars, and restaurants. Our product starts eliminating flies immediately. Our gel eliminator coats your pipes, leaving a gel coating on them. Use in your sinks and drains to help get rid of those drain flies. Our repellent works hard at eliminating even the worst of infestations Simply pour our drain fly repellent straight down the drain to start eliminating drain flies. Our drain gel fly repellent is safe for drains, pipes, and septic systems. Great for commercial use in kitchens, bars, and restaurants.