Edible
Leaves of this plant have also been called "Poor Man's Spinach." They can be steamed like spinach (or eaten raw, if the plant is young enough) or also made into tea. The leaves are rich in vitamins A and C, as well as many minerals. The seeds are very high in B vitamins.
Medicinal
Plantain is a soothing herb and is good first-aid for minor cuts, bruises, bites and bee stings. Just find a leaf, chew it up, and slather all over the irritated part! It sounds gross, but plantain is so easy to find that you almost always have some nearby.
The Experts Say...
(Note: affiliate links below)
Field Guide to Wild Edible Plants: Older plants are best appreciated with a cream sauce, after the plant has been pureed and pushed through a sieve to remove the stringy parts.
The Herbal Drugstore: useful in treating bronchitis, burns, colds and flu, hemorrhoids, poison ivy, oak & sumac, sore throat and sunburn.
The Herbal Home Remedy Book: when seeds are eaten with the husks on, they work as a safe and gentle laxative.
Tom Brown's Field Guide to Wilderness Survival tells us that plantain can be used as a toothpaste/poultice and insect repellent (take 1 or 2 seed pods daily). The seeds can also be ground and cooked up like cereal.
Now go have fun and chew up some plantain! At least it gives you something to do when you're stuck way out in left field.
-Bethany