As the name would suggest, heal-all has been used to treat all kinds of maladies in the past. Traditionally, the shape of a plant was often used to discern its medicinal uses, and so the shape of this flower, with its open mouth exposing the throat, led to it being used as a gargle to treat sore throats! It was later found to be effective in treating a wide variety of wounds and skin infections. The anti-viral properties of the plant are particularly notable.
The square stem will tell you this is a member of the mint family. The leaves are lance-shaped, and the leaf margins are smooth to slightly toothed. The arrangement of the leaves is opposite. (See the photo gallery for a close-up of the leaf.)
The flowers of heal-all are arranged in a whirl-like fashion around a squarish cluster. The purple/violet flowers have an upper lip that is hooded and a lower lip that has 3 whitish lobes. The middle lobe is ornately fringed, as you can see in some of the photos.
Heal-all is not native to the U.S., but nonetheless, it is now found throughout North America. Bloomtime is June through August. You can find it growing in disturbed areas like roadside ditches or along trails. Some of these photographs were taken along a woodland trail near Pandapas Pond in Montgomery County. The rest were found in the edge area between a hayfield and the forest.