Pharmacological approaches have been included in conventional medical treatment for insomnia or sleep disorders. However, long-term use of frequently prescribed medications can often lead to habituation, critical withdrawal symptoms and/or side effects. Some individuals with insomnia or trouble sleeping have used complementary and alternative medicine (CAM) therapies to treat their conditions. Recently, CAMs or herbs have been attractive alternative medications to many patients with sleep disorders who may be averse to using conventional drugs. We reviewed the most widely available sleep-promoting herbs commonly used in the western and oriental countries.