Multiple sclerosis (MS) is a neurological condition that is estimated to affect around 60,000 people in England and Wales, with a lifetime risk in the UK of 1 in 1,000.(1,2) Spasticity (an increase in muscle tone) is a common symptom of MS, resulting in muscle spasms, immobility, disturbed sleep and pain.(3,4) Complex drug combinations are sometimes necessary to manage symptoms of MS, but these are often only partially effective and associated with unacceptable side effects.(5) Cannabis extract containing delta9-tetrahydrocannabinol (dronabinol) and cannabidiol are the principal extracts from the cannabis plant present in a licensed preparation (▾Sativex - GW Pharma Ltd), the first cannabinoid preparation to be approved for medical use. Sativex has been licensed "for symptom improvement in adult patients with moderate to severe spasticity due to MS who have not responded adequately to other anti-spasticity medication and who demonstrate clinically significant improvement in spasticity related symptoms during an initial trial of therapy".(6) Here we review the evidence for cannabis extract and its place in the treatment of the condition.