Mauro says:

Herb Lore
Peppermint (Mentha piperita)
The History
Used as a magical herb ever since the time of the Chaldeans, it was common among the Ancient Greeks to throw bundles of dried peppermint in the funeral pyre of warriors fallen in battle, peppermint being Ares’ sacred plant.
It was immensely popular among Medieval magicians, who attributed to it the wildest powers (for example it was an infallible cure for ailing beehives). Muslim alchemists and mystics took a particular liking to it and to this day it’s the most widely used and beloved essence of the Muslim world.
The facts
Mint essence has been shown to be a very mild aphrodisiac and analgesic and a good digestive.

Wormwood (Artemisia absinthium)
The History
Commonly associated with the infamous absinthe (of which it is just one of the component parts) and the Decadent movement, it has long been a magical herb.
Avicenna (Ibn Sinna) and physicians of the Salernitan School (ie the most influential medical school in Medieval Europe) studied its effects and concluded it was useful to combat seasickness and recover lost appetite after a long illness.
In some European countries a plant of Wormwood, cut just above the root and hung upside down from the ceiling on St John’s Day was sure to keep tears and sorrows away from the house. The plant should be renewed each year and the old one burnt to ensure success.
The Facts
In small doses Wormwood can be useful to fight depression and stimulate an healthy appetite. It has long be believed to facilitate pregnancy though this fact has never substantiated by clinical studies.

Rosemary (Rosmarinus officinalis)
The History
Widely used as a cooking spice or as a simple essence, very few suspect the humble Rosemary to be a "ritual" herb. As such it has been used by the Ancient Egyptians: a stalk of Rosemary was put in the Pharaoh’s sarcophagus as a love token for his righful spouse, Isis.
It has been used by men asking for a women’s hand in marriage for longer than anyone can remember and has always been used in the Mediterrean area for some simple exorcising rites.
The Facts
Apart tasting great (I make up a great steak sauce using Rosemary, Parsley, Mustard, Vinegar and a little Sunflower oil), Rosemary has digestive properties, is a mild nervous stimolant and has long been believed (though not proven) to be good for the skin.

I knew Mugwort was once used as a "poor man’s tea" or as a substitute for hops…
Anyway it’s closely allied to the Wormwood (both belong to the genus Artemisia) and both herbs are connected with St John.
Mugwort (in parts of Holland and Germany) was believed to have been worn as a girdle by John the Baptists and was gathered for medical purposes on St John’s day.
It has slight tonic properties and was once used as a cure for epilepsy.
Burdock, also called Lappa or Beggar’s Buttons, (Arctium lappa), is notable in the fact that no animal (except for the ass) will browse on its leaves.
Hyssop (Hyssopus officinalis) has been as a curative herb for centuries: as such it was mentioned in the Holy Bible. It was once used to fight pulmonary diseases and as a carminative (ie to fight flatulence).
Blessed Thistle (Carbenia benedicta) has been introduced to Britain, being a native of Southern Europe, probably some time during the XVI century. This was a cure-all herb, and as such even mentioned by Shakespeare in Much Ado About Nothing. The Blessed Thistle is rich in cnicin, an anti-inflammatory substance, which is apparently a very good substitute for aspirin (as is salicin, derived from willow bark). The astounding success of commercial, mass produced aspirin made these traditional anti-inflammatory methodsredundant but now they are being recovered because of alleged anti-cancner capabilities.
PS while we are at it: the Spartans valued the willow above any other plant or herb. Infusions made from its bark proved invaluable to old veterans ridden with rheumatism and war wounds.