Ingredients in your horse’s fly spray!


Flies are about the biggest pain in the butt. You need to control them environmentally as well as on your horse. Read more here to understand how to attack and manage flies. Most of us like to use some sort of repellent – and you have some choices there – but what are the ingredients in fly spray?

Fly sprays have a long list of ingredients – which can be broken down into a few categories:


  • Repellents


  • Insecticides (kill the flies)


  • Carriers


  • Fragrance


  • Conditioners


  • Pyrethrin life extenders (prevent the active ingredients from breaking down so quickly…)


Also, know that the above ingredients can be natural or synthetic. The following is a brief introduction to some of the common ingredients in fly sprays.




It’s always a good idea to know what you are putting on your horse!


  • Some fly sprays that you can pick up at your local tack shop contain pyrethrins. Pyrethrins are organic compounds that are derived from chrysanthemum flowers and are biodegradable. Pyrethrins act on the nervous systems of insects, which makes them an insecticide.


  • Pyrethroids are man-made pyrethrins, and cypermethrin and permethrins are examples. These are toxic to fish and other aquatic animals and are also an insecticide. Pyrethroids are more stable than pyrethrins, and therefore provide longer protection.


  • You may also come across piperonyl butoxide (BPO), which is basically a steroid for pyrethroids and pyrethrins, increasing their potency. BPO does nothing by itself!


  • You may also find lots of oils in a fly spray bottle, including peppermint, citronella, and eucalyptus. For the most part, these are natural and very effective against mosquitos but may have limited effects on biting stable flies.



When applied according to directions, and using safe methods (like not spraying your horse’s face), you will have success with fly sprays.


  • Used in combination with fly sheets and masks, you will be good to go. Use a mitt, cloth, roll on, or your hand to apply any fly spray to your horse’s more sensitive areas, like the exterior of ears and down the face. I don’t like to apply anything above the eyes, mucous membranes, or under the tail just in case it runs down.




Fly control products can be roll-on, sprays, even lotions and goops.



  • You also have the option of making your own fly spray, and there are about a zillion recipes out there. Here’s a list of things NOT to put in your homemade fly spray (and yes I have seen recipes with these things in them….) Avoid oils that are designed for burning or fuel. Citronella oil has two forms – the kind you use in torches, and the non-burning kind. Please no kerosene. Please no household detergents or cleaners.


  • Some of the more common recipes include skin-so-soft, natural oils, and in most cases that use oils, some sort of emulsifier (like soap or polysorbate 20) which acts to blend the oil and other water-based ingredients. This article has loads of ideas, too.


  • I have often mixed skin so soft with water (about a 1 to 5 ratio SSS to water) and had pretty good results!


  • There are some new fly sprays that contain weird-smelling, but effective, fatty acids. These serve to change the way your horse’s own scent is, which camouflages him and the flies can’t find him. I also spray some of this around my horse’s stall.



fly spray on legs.jpg

Fatty acid fly sprays are usually applied to bellies and the backs of legs.


I understand that many of us really like to be as natural as possible when it comes to our horses and therefore like to create our own recipes.


  • I also understand the there are a million products out there for fly control for those of us that hate to “cook”!


  • There is no right or wrong answer *usually*, just what works for you. Just follow the directions, and be super diligent in monitoring for possible skin reactions. Also, remember that fly spray is only one way you need to attack flies.


Just for good measure – if you do try a fly spray that causes an irritation – call your Veterinarian and get thee to a wash rack! Lots of mild shampoo and unbelievable amounts of rinsing.






If you want to pick up some roll-on fly control, use these links. As an Amazon Associate, I earn from qualifying purchases. There is NO extra charge to you, and I thank you for your support!


Farnam Roll-On Fly Repellent for Horses, Ponies and Dogs, 2 fl oz