The call of Nepeta cataria!

Walking in the countryside and foraging whatever herb is in season is one of my favourite activities, but I also love to hang around in places selling plants, particularly Cherry Tree Nursery in Bournemouth, a charity based on horticulture providing support to people with mental illness. Their plants and herbs and trees are beautiful, mostly kept outside, and cared for without forcing growth. It is lovely to stroll amongst the plants, bees busying around the flowers, green lushness clearing the mind, and waiting for a particular plant to call you.
Last saturday, the attraction came from catnip and I couldn't resist to get some for my garden.

A member of the Lamiaceae family (it is a mint), catnip is an aromatic perennial with heart shaped leaves and whorls of white flowers. In herbal medicine, the arial parts are used and gathered when in flower in summer and autumn.

It's chemical constituents include iridoids, tannins and volatile oils. It produces nepetalactones, which are iridoids used by the plant as an herbivorous insect repellent. Nepetalactones can indeed repel insects with efficiencies comparable to the synthetic repellent DEET. On another hand, possibly by mimicking feline pheromones, they have quite a contrary effect on these animals, attracting them and inducing playful actions such as rolling over and pawing.
In the human body, nepetalactones from catnip are similar to valepotriates from valerian and produce a very relaxing and calming effect. But they are only some of the plant's constituents and together with all the other chemicals it contains, catnip has multiple effects.

It is a carminative, antispasmodic, diaphoretic, nervine and slightly astringent herb.
As an antispasmodic, it is useful in intestinal colics, cramps, menstrual cramps, IBS...
Catnip is markedly antiflatulent, helping to settle indigestion and colic (Andrew Chevalier) and moreover it is beneficial in headaches associated with digestive issues.
Diaphoretic, catnip is a godsend for colds and flu, and as a first aid to bring down fevers, opening the pores and stimulating sweating, supporting the body to fight infection.

Gentle and caring, this herb is of great value for children and is helpful in fevers, colics, nervousness. William LeSassier explains that it is particularly suited to the 'quiet, nervous, overactive and restless child' (Wood M.).

Nicholas Culpeper, in 17th century, wrote about catnip that it is of 'special use for the windiness of the stomach and belly. It is effectual for any cramp, or cold aches, to dissolve cold and wind [...] and is used for colds, coughs, and shortness of breath.' He also mentions that the juice of the herb made up into an ointment is effective for hemorrhoids.

Catnip can be used as infusion or tincture, by itself or associated with other herbs.
Infusion of catnip, yarrow and peppermint: digestive infections
Infusion of catnip and fennel seeds: to relieve bloating and flatulence
Infusion or tincture of catnip and black haw (dried bark): menstrual cramps
Hot infusion catnip and elder flowers or berries: colds, flu and fevers

To make an infusion, 1 or 2 teaspoon(s) of the herb can be used per cup of hot water, cover for 15 minutes in order to preserve the precious volatile oils, then strain and drink.

References

American Chemical Society (2010), Nepetalactone. [online] Available at:
https://www.acs.org/molecule-of-the-week/archive/n/nepetalactone.html

Chevallier A., The Encyclopaedia of medicinal Plants (1996)

Culpeper N., Complete Herbal (original text 1653, edition 2007)

Hoffmann D., Medical Herbalism (2003)

Lichman BR., Godden GT., Hamilton GP., Palmer L., [...] , and O’Connor SE. (2020). The evolutionary origins of the cat attractant nepetalactone in catnip. Science Advances. [online] Available at: https://www.science.org/doi/10.1126/sciadv.aba0721

Wood M., The Earthwise Herbal (Vol 1) (2008)