Nytol Herbal Simply Sleep & Calm Elixir Nytol Herbal Simply Sleep & Calm Elixir provides temporary relief from the symptoms of mild anxiety such as exams & stress at work. It can also be used to aid sleep. Nytol Herbal Simply Sleep & Calm Elixir is a herbal medicinal product containing extracts of Valerian root, which has been used traditionally to induce sleep & promote calm.