Insect Bites and Stings

Insect Bites and Stings

Say "insect repellent," and the brand names that jump into most people's minds all contain a chemical with a name that's so long, only a chemist could pronounce it. The rest of us call it DEET.

I confess I'm much opposed to DEET. It dissolves my plastic glasses, and once on the skin, it quickly passes through the skin into the bloodstream, where I don't want synthetic chemicals with tongue-twister names.

In some circumstances and in some places, DEET is banned altogether. At the Amazonian Center for Environmental Education and Research camp on the Napo River of Peru where I conduct some of my workshops, for example, they prohibit any use of DEET. This has nothing to do with its effect on people. They've banned the chemical because it speeds the deterioration of the synthetic fibers that hold up the canopy walkway that meanders through the tree branches, sometimes 100 feet above the forest floor.

Green Pharmacy for Repelling Insects

Of course, while I don't care much for DEET, I don't care much for bugs either. I've spent years trying out various herbal insect repellents, and I have reasonably good news to report.

Mountain mint (Pycnanthemum muticum) and pennyroyal (Mentha pulegium or Hedeoma pulegioides). Both of these herbs contain pulegone, a powerful insect repellent. Pennyroyal is the more popular of the two, and it has a long and honorable history. Pliny noticed in the first century a.d. that it was effective against fleas. In fact, this herb's insect-repelling action is incorporated into its scientific name: Pulegium means "flea" in Latin. You can find pennyroyal in many commercial herb-based insect repellents.

Based on my experience, however, mountain mint works better than pennyroyal. If you have access to fresh mountain mint, just pick some leaves and rub them on your skin and clothing. (But don't use pennyroyal or mountain mint if you're pregnant, as the ingredients in these herbs have been known to increase the risk of miscarriage.)

Pennyroyal Pennyroyal has been called fleabane, tickweed and mosquito plant because of its power to repel insects.

Basil (Ocimum basili-cum). Basil is mainly a spice in this country, but elsewhere it is used extensively in medicine, particularly in India. Indians rub the leaves on their skin as an insect repellent, and Africans do the same. If I were bothered by bugs in my garden and some of my culinary basil was close at hand, I might rub some on as an impromptu insect repellent.

Citronella (Cymbopogon, various species). A lemon-scented plant from Asia, citronella has long been used as an insect repellent. It's often sold in candles that are burned to drive off mosquitoes. It's also the active ingredient in several non-DEET commercial insect repellents that you can apply to either your skin or your clothing.

As with many essential oils, pure citronella oil can be irritating to the skin (and it should never be ingested). If you want to use the oil, you'll have to dilute it by adding several drops to a vegetable oil base. You can rub the diluted oil directly on your skin.

The knock on citronella is that its protection wears off faster than DEET's. In one experiment, citronella oil repelled the mosquito that carries yellow fever for only a little over an hour, so maybe you should use DEET if you live in an exotic area where yellow fever is still a problem. But for American backyards, citronella works reasonably well.

A while ago, I received a most welcome letter from a high school student, Rachel Smith. I had sent her some information about essential oils, including citronella, to help her with her science fair project, "Essential Oils as an Alternative Pesticide." She won a prize based on her demonstration that citronella oil, and to a lesser degree, teatree oil controlled aphids
on her hibiscus plants. I was not surprised.

Citrus essential oils. Something about citrus, and plants with citruslike aromatic qualities, repels insects. The Citrosa geranium, for example, which has a strong citrus smell, has 30 to 40 percent of the repellent power of DEET. And crushed lemon thyme (Thymus citriodora) has 62 percent of DEET's repellency.

For this reason, it seems to me that any citrus-scented essential oils, including those of citrus leaves themselves, would be better for the user than DEET. After all, our ancestors were exposed to citrus fruits as they evolved. You sure can't say the same thing about DEET.

If you want to try citrus essential oils, you'll have to dilute them first by adding several drops to a vegetable oil base. You can experiment with using a couple of essential oils together. You might be able to customize an insect repellent that will also serve as a scent that is pleasing to you. I mean this for men, too; many men's colognes feature citrus scents.

Lemongrass (Cymbopogon, various species). This is a close kin to citronella and has many of the same insect-repellent compounds. If you have access to the fresh herb, simply crush some and rub it directly on your skin.

Assorted essential oils. I should also mention an herbal essential oil combination that I encountered on a 1995 trip to Amazonian Peru. I was amazed at the efficacy of a repellent given to me by North Hollywood herbalist John DuVall. It contained citronella, lavender and pennyroyal in a vegetable oil base, and it was the most effective repellent I've ever witnessed for the bugs down on the Napo River. A drop in the center of a sweaty red hat created a bull's-eye--a bright red, bug-free spot, surrounded by a solid brown horde of sweat bees. The shaman I was working with at the time, Antonio Montero, was more impressed with the aroma, saying that it contained "the spirits of the world."

Unfortunately, I don't have the complete recipe for this repellent, but you could experiment by mixing several drops of each of these oils into a vegetable oil base and see if you find a formula that works for you. Just remember never to ingest essential oils.

Green Pharmacy for Insect Bites and Stings

Doctors generally recommend pain relievers, ice packs and meat tenderizer to treat insect bites and stings. (Applying a dab of commercial meat tenderizer directly to a sting neutralizes venom.) These are all reasonable approaches. There are also a number of good herbal alternatives.

Calendula (Calendula officinalis). I'm a fan of Maude Grieve, whose Modern Herbal, written in 1931, is now a classic in the field. Grieve writes picturesquely that calendula flower "rubbed on the affected part, is an admirable remedy for the pain and swelling caused by the sting of a wasp or bee." I believe her, and I would try it if I were stung and had some fresh calendula close at hand.

Garlic (Allium sativum) and onion (A. cepa) Both garlic and onions contain enzymes that break down chemical substances known as prostaglandins that the body releases in response to pain.

Interestingly enough, garlic and onions work both internally and externally. You can make a poultice of these herbs and apply them directly to insect bites and stings. You can also get a measure of relief by eating foods that contain them.

One further note: Onion skin is an extremely good source of the anti-allergic chemical quercetin, which is especially good for relieving inflammation. You can get the added benefit of quercetin by leaving the skin on when you cook soups or stews. Fish out the skin just before serving; it will have released a good amount of quercetin into the dish, along with a rich, brown color.

Plantain (Plantago, various species). Wherever I go--from the Appalachians to the Andes to the Rockies--plantain is one of the first herbs my botanical friends mention for bug bite. It's the first thing I apply at home, too, since it is a common weed in my lawn. (You need to rub on the fresh herb for this remedy to work.)

Edward E. Shook, author of Advanced Treatise on Herbology, tells a story about a woman who got a bee sting on her hand, and her entire arm began to swell. He told her to wash plantain leaves, make a poultice and apply it to the sting. The next day the woman returned, healed. I didn't see this happen, but I do know that plantain is many herbalists' herb of choice for bee stings.

Assorted herbs. My database also lists a few other folk remedies for insect bites and stings: camomile, flanders poppy, indigo and St.-John's-wort. The typical approach is to rub the fresh herb on the site of the bite or sting. None of these would be my first choices, but if I were caught without the herbs discussed above, I'd try any one of these.