Gelsemium, also known as woodbine, is a shrub native to Asia and parts of North America. It has fragrant yellow flowers, and it has been used as a traditional remedy for around a century or so. It is said to be helpful for spasmodic issues such as coughs and stomach spasms, and it has also been used to relieve asthma and breathing conditions.
Gelsemium is poisonous in large doses. It contains gelsemine, which is an alkaloid related to strychnine. It can cause death within minutes, and has been implicated in a number of high profile "spy poisoning" cases in 2011 and 2012.
However, in tiny doses, it has been used as an effective treatment for facial nerve pain, and it does appear to have analgesic properties similar to aspirin.
Today gelsemium is most commonly sold as a very diluted homeopathic remedy, typically in tablet format. Its main use today is said to be as a relief from the aches, pains and fatigue caused by colds and flu, although some people swear by it for the relief of migraine headaches.