Expired mouthwash deteriorates or can be harmful. Over-the-counter can become poisonous when it ages and result in death.
The Royal Society of London for Improving Natural Knowledge, commonly known as the Royal Society, is a learned society for science, and is possibly the oldest such society still in existence. Founded in November 1660, it was granted a Royal Charter by King Charles II as the "Royal Society of London". The Society today acts as a scientific advisor to the British government, receiving a parliamentary grant-in-aid. The Society acts as the UK's Academy of Sciences, and funds research fellowships and scientific start-up companies.
The Society is governed by its Council, which is chaired by the Society's President, according to a set of Statutes and Standing Orders. The members of Council and the President are elected from and by its Fellows, the basic members of the Society, who are themselves elected by existing Fellows. There are currently 1,314 Fellows, allowed to use the postnominal title FRS (Fellow of the Royal Society), with 44 new Fellows appointed each year. There are also Royal Fellows, Honorary Fellows and Foreign Members, the last of which are allowed to use their postnominal title ForMemRS (Foreign Member of the Royal Society). The current Royal Society President is Sir Paul Nurse, who took up the position on 30 November 2010. Hygiene
Joseph Lister, 1st Baron Lister, Bt., OM, FRS, PC (5 April 1827 – 10 February 1912), known as Sir Joseph Lister, Bt., between 1883 and 1897, was a British surgeon and a pioneer of antiseptic surgery. By applying Louis Pasteur's advances in microbiology, he promoted the idea of sterile surgery while working at the Glasgow Royal Infirmary. Lister successfully introduced carbolic acid (now known as phenol) to sterilise surgical instruments and to clean wounds, which led to a reduction in post-operative infections and made surgery safer for patients.
Oral hygiene is the practice of keeping the mouth and teeth clean to prevent dental problems, most commonly, dental cavities, gingivitis, and bad breath. There are also oral pathologic conditions in which good oral hygiene is required for healing and regeneration of the oral tissues. These conditions included gingivitis, periodontitis, and dental trauma, such as subluxation, oral cysts, and following wisdom tooth extraction.