Mints are aromatic, almost exclusively perennial, rarely annual, herbs. They have wide-spreading underground and overground stolons^[6] and erect, square,^[7] branched stems. The leaves are arranged in opposite pairs, from oblong to lanceolate, often downy, and with a serrate margin. Leaf colors range from dark green and gray-green to purple, blue, and sometimes pale yellow.^[5] The flowers are white to purple and produced in false whorls called verticillasters. The corolla is two-lipped with four subequal lobes, the upper lobe usually the largest. The fruit is a small, drycapsule containing one to four seeds.

While the species that make up the Mentha genus are widely distributed and can be found in many environments, most Mentha grow best in wet environments and moist soils. Mints will grow 10–120 cm tall and can spread over an indeterminate area. Due to their tendency to spread unchecked, mints are considered invasive.^[8]

 

Mint was originally used as a medicinal herb to treat stomach ache and chest pains, and it is commonly used in the form of tea as a home remedy to help alleviate stomach pain.^[13][14] In Rome, Pliny recommended that a wreath of mint was a good thing for students to wear since it was thought to "exhilarate their minds". During the Middle Ages, powdered mint leaves were used to whiten teeth.^[15] Mint tea is a diuretic.^[16][17] A common use is as an antipruritic, especially in insect bite treatments (often along with camphor).^{[citation needed]} The strong, sharp flavor and scent of mint is sometimes used as a mild decongestant for illnesses such as the common cold.^[18][19] Mint is also used in some shampoo products.

Menthol from mint essential oil (40–90%) is an ingredient of many cosmetics and some perfumes. Menthol and mint essential oil are also much used in medicine as a component of many drugs, and are very popular in aromatherapy. Menthol is also used in cigarettes as an additive, because it blocks out the bitter taste of tobacco and soothes the throat.

Although it is used to treat many symptoms, mint can also cause allergic reactions to some people. Although rare, these can induce painful symptoms including abdominal cramps and diarrhoea, headaches, tingling or numbing around the mouth, nasal congestion, clogging of the sinuses, nausea, etc. It can be a reaction to Salycilates^[20] or Linalol contained in the mint, or to some of the proteins inside the plant. It is possible to have high intolerance to one type of mint such as spearmint yet have no reaction to other types such as peppermint and menthol, and the symptoms may get worse over time. Because it is uncommon, the people who suffer from mint allergies can find it hard to deal with it on a daily basis. Most of the problems arise from the need to find special toothpaste or dental products, but can also be reactions to the smell of somebody consuming mint candy or gum in a public or work place. In some cases it can be a minor disturbance but sometimes a severe reaction: because it is potent, inhaling the mint can trigger by itself breathing problems, nausea and dizziness separately or all together. Depending on whether the allergy is to a chemical or a protein inside the plant, it may or may not extend to other Lamiaceae.^[21]