Spearmint occurs naturally in Eurasia and on Canary Islands. Wild kingmint occurs rarely in Scandinavia up to Jämtland and Nordland county, but in Finland only in the southernmost parts. The plant is found in some places in the United States, but is not native there.
The essential oils from Kungsmyntan are powerful and aromatically fragrant.
The dominant substance is thymol, which is also found in thyme. Thymol is both disinfectant and antispasmodic and works very well in severe cases coughing attacks (eg whooping cough). The substance also has a killing effect on fungi and parasites of several kinds of intestinal worms.
Because spearmint contains much less thymol than thyme, it has been overshadowed in modern medicinal use. However, it can partially replace thyme in cough mixtures. The antispasmodic effect is enhanced by the addition of small amounts of the insectivorous plant sileshair. Tea off spearmint stimulates digestion and can also be used as a gargle for inflammations in the mouth and throat. In addition to the disinfection effect of the thymol, the tannins in the plant also suppress bacterial infections.
Spearmint is also known to have a strong antioxidant effect.