A grass plant called rush were introduced from India to Japan via the Silk Road. Rush was used as a tatami material for the nobles around 1,300 years ago and became common for the people after the Edo period. The central portion of rush is made of spongy-like structure called “nakago”, which plays an important role in humidity adjustment by absorbing extra moisture or humidifying. Therefore rush has been used as one of the most suitable building materials for Japanese houses in a high-humidity environment. Rush absorbs one third of night-sweats when it’s used as bedding, and this promotes a comfortable sleep without sticky feeling. Moreover, rush absorbs toxic substances including nitrogen dioxide and/or formaldehyde generating from tobacco or heaters. Therefore rush is also used as a glue of flooring materials and wall papers in recent years. Rush has a high antibacterial effect against salmonella or escherichia coli O-157 which are the causes of food poisoning, and this is about 5.5 times higher than cotton cloth. Moreover, rush has the aroma component called “phytoncide” resembling forest trees. Therefore, rush provides the relaxation effect just like a forest bathing in a house to our life.