Catnip

The Elizabethan herbalist Gerard noted: "They do call it herba cataria and herba catti because cats are very much delighted herewith, for the smell of it is so pleasant unto them that they will rub themselves upon it and wallow or tumble in it and also feed on the branches and leaves very greedily."

What cats are actually fond of is a component of the mint's oil called nepetalactone (C₁₀H₁₄O₂), a relatively simple organic compound.
 
Besides being grown for the enjoyment of cats, catnip has a history of use as a beverage and a medicine. Before European trade with China began bringing large quantities of fine eastern tea to Europe, catnip tea was a domestic favorite especially among tea loving residents of the British Isles. When growing the plant for this purpose, mature leaves should be collected while they are still fresh and dried in the shade (not in the sun, or the volatile oil will be lost) for several days. One teaspoon of the dried herb is then added to each cup of boiling water and allowed to steep. The tea should not be boiled or, again, the oil will be lost. The drink is an excellent source of vitamin C. (Family: Lamiaceae)