Many people have heard of St. John’s wort, often as an herbal aid for depression. But St. John’s wort is also a marvelous herb for your skin.

Surprised? Well, many herbs have both internal and external uses, and St John’s wort is no exception.

This wonderful herb has been used for hundreds of years for nerves. We have nerve cells both inside our bodies (the central nervous system, where neurotransmitters regulate our moods) and in our skin, where nerves let us know if we’re hot or cold, or if our skin (our body’s outer defense layer) has been hurt in any way, such as scratches or insect bites or sunburn.

Over the years, many cultures observed that a plant’s shape and/or growth seemed to roughly correlate to parts of the human body. People realized that the herb, or the relevant part of it, benefits the corresponding area of the body (in Christianity, this was known as the “Doctrine of Signatures”).

It is easy to make a beautiful, dark-red oil from St. John’s wort to be used directly on your skin, or add to salves and lotions.

All you need is a clean, dry jar with a lid, good-quality olive, sweet almond oil, or other vegetable oil (preferably organic), and a nice stand of the plant in bloom.

St. John’s wort is easily identified with the help of a good field guide. The cultivar you want is known botanically as Hypericum perforatum, the “perforatum” of the species name referring to little translucent glands scattered throughout its leaves, somewhat mimicking the nerves and glands of our skin.

Other species of Hypericum don’t have the constituents that are needed, so even if you have a beautiful ornamental St. John’s wort shrub in your yard, resist the temptation to use it –you’ll get disappointing results.

St. John’s wort grows in sunny fields and roadsides, as well as partial shade. I was surprised one year to find it taking over the woodsy hill in my backyard!

It blooms from the middle of June until August or September, though less profusely after July. The herb got its name because it blooms around St. John’s Eve, June 24.

So, on a beautiful, sunny day, when dew or rain have dried off the plants (usually late morning), take a pair of scissors and a basket or paper bag and go harvest St. John’s wort tops.

Take only the top quarter of the plant (flowers, buds, possible seed heads, leaves, and stems). All these parts contain active ingredients.

Two cups loosely packed is enough.

This allows the perennial plant to keep growing and blooming so it can come back next year.

Be aware of where you are picking. Do not take plants closer than a few yards next to a highway or busy street, or from an area you know or suspect is contaminated with lead or other chemicals/heavy metals. Remember that whatever goes onto your skin gets absorbed into your body to some extent.

When you get home, spread the St. John’s wort out to wilt for a few hours or overnight, or place in a very low-temp oven for a short time. This gets out some of the moisture, so your oil is less likely to mold. It is called fresh-wilting.

Next, cut up the plant material to some extent.

Lightly pack the St. John’s wort into your clean jar. You don’t want to cram as much plant material as possible into the jar, but you also want more than a few sprigs of herb. The herb matter should be slightly springy.

Pour the oil in and fill the jar to a little above the top of the plant matter, then take a skewer or chopstick and stir to get air bubbles out.

Screw on the lid.

Label your jar with the date, the herb, and the kind of oil you used.

Check the jar the next day and add more oil if necessary, because the plants may have absorbed some and the level may have dropped. Make sure plant material is completely covered, because any plant matter that is above the oil, in air, can easily cause molding. You can shake the jar to get the herb and oil to combine more completely.

Depending on your preference you can leave your oil on a sunny windowsill or place it in a dark cupboard. Either way, put it on a plate or something oil-resistant! Some of the oil will inevitably ooze out of the jar. Let this mixture brew for six weeks (if you’re in a hurry, 4 weeks will do), checking it occasionally and stirring out air bubbles.

After six weeksyour oil may go bad if you wait too long. Using cheese cloth or clean muslin (don’t use a coffee filter or paper towels, the pores are too fine and will clog up), strain out the plant matter, then squeeze out any leftover oil from the plant matter.

Put your infused oil into another clean, dry jar. Label this jar also.

The oil will last for several years, especially if you keep it refrigerated or in a cool place.

You can use the oil directly on your skin, or as the base for salves and lotions. St. John’s wort oil is a great soother for sunburn, sun-poisoning rash, and some eczemas. It is also a fine moisturizer. Traditionally St. John’s wort has been used externally to help with nerve pain.

Remember not to use it on open wounds, and always consult a health-care practitioner about any skin problems.