Supporters claim that it helps to treat conditions such as asthma, eczema, bronchitis and cystic fibrosis.
The treatment quickly became popular across eastern Europe but has only recently been pioneered in London. The first salt grotto in London is believed to have been the Salt Cave in Earlsfield, and a clinic in Acton called Adalex also offers salt therapies.
A home with what is believed to be Britain’s first in-house salt cave has come on to the market to rent for £20,000 a month. The grotto is part of the seven-bedroom home’s Swarovski spa, gym and indoor pool complex.
This year’s “must have” spa facility for London’s grandest mansions is a salt grotto, say agents.
Breathing in the minerals in salty air has been linked with good health since the Ancient Greeks but only became a recognised therapy in 1854 when a Polish health official noted salt miners suffered remarkably little from lung diseases.
The St John’s Wood residence is close to another property with planning permission for a basement salt grotto. Star Wars bubble bath tycoon Robert Beecham won consent for the vast basement in November 2015 that includes a cave for “speleotherapy”.
Stevie Walmesley, lettings manager of Knight Frank St John’s Wood, said: “Taking home beauty rooms to the next level, salt grottos are the latest must-have in the luxury lettings market and set to be huge here in the UK in 2017.”