I had a friend who fostered children often and just a few years ago, a set of young children came into their home with this super resistant lice. I watched this poor gal try everything (from a distance of course). She went for the OTC stuff, took everyone to the doctor, tried tons of natural or DIY remedies. Then finally she found it! Listerine, yes, that did the trick after about 2 months of battling this horrible super lice, Listerine (you can use the off name brand, but it has to contain the same ingredients) kicked it in the butt. All she did was take each child/person and pour the Listerine on the head completely and wrap in clear plastic wrap daily. Leave on for about an hour and then your free to rinse out. She only had to do this for a few days it was done. You must repeat a few times, for the next week or two to kill any hatched eggs. *I have personally used this on animals with mange and seen quick results.
What makes this mouth cleaner so effective? Thymol is the number one potent ingredient but there are a few other. Yes, made from Thyme Essential Oil, thymol is the active component and a very effective pesticide/repellent, parasite expectorant and germ fighter. The herb itself is simply not enough to do this, you will need a form of the oil. Either an essential oil or a product that contains it.
There are a few others in the correct mouth wash that help this fight pests as well as germs so effectively. They are (picture of label above) Menthol, from Peppermint Essential Oil and Eucalyptol from Eucalyptus Essential Oil. Together these are the active ingredients (a power house) that both kill and repel pests and are why the mouth wash is so effective. If you did not have the mouth wash on hand you could combine these three essential oils. Again it's the oils, a very concentrated form of the plant components, not the herb itself that give this remedy its power. However, the mouth wash is much cheaper and I advise keeping a bottle, or two, on hand for an emergency situation. *You can also wash (blend with dog shampoo) or spray animals with this for mange and other pests that may burden your homestead. Put into a spray bottle undiluted to rid chickens of any lice or mites. Spray a few times a day. You will see results within days. Hope you found this post helpful!