I don't know if this works with yellow fly bites, but it's worth trying. When I was bitten by so many noseeums in Sanibel a few years ago, I searched online for a way to stop the itching. A few sites said to blow hot air from a hair blower on them. They stopped itching immediately and it lasted for 3-6 hours (enough to get a decent night sleep). It also turns out that I have a sun allergy now and my legs and arms get itchy when exposed to sun. I use the hair blower on my arms and legs and that works, too. Be careful not to burn yourself with the hot hair blower and I don't think you can use the hair blower on someone else because you could burn them. Also, I don't know if there are any downsides to this (other than getting burned), but I've been doing this for a few years now and it works every time without taking any medication or putting on any creams. My friends have tried it and says it works for them. Any doctors on SoWal know why it works? To kill the flies/mosquitoes before they get you, get one of these electrified racquets from Amazon.com: Amazon.com : Electric Bug Zapper Racket Fly Swatter 【VIAEON】 Fly Killer Bugs Zapper Wasp Traps Mosquito Outdoor Pest Control : Patio, Lawn & Garden We went on vacation in Maine and friends had some of these and they were great electrified swatters that killed a lot of annoying bugs. Works for fruit flies and flies in the house, too, but flies are hard to catch. I used Cactus Oil as well and you can get it at Seacrest Sundries and online. It does a good job of keeping biting flies away when at the beach (but the electric swatter is more fun). Good luck!