MUltiple Sclerosis and Extract of Cannabis (MUSEC) Study

Inclusion Criteria: * Signed informed consent. * Diagnosis of MS according to McDonald criteria. * Current muscle stiffness ≥ 4 on a 11-point categorical rating scale. * On-going troublesome muscle stiffness for at least 3 months. * Stable disease for the previous 6 months. * Antispasticity medication and physiotherapy stabilised for the last 30 days. * Patients may be ambulatory or not. * Age 18-64. Exclusion Criteria: * Immunosuppressants which may affect spasticity (including corticosteroids and interferon but ex-cluding azathioprine) taken currently or in previous 30 days * Past or present history of psychotic illness. * Open/infected pressure sores or other source of chronic infection. * Significant fixed tendon contractures. * Severe cognitive impairment such that the patient is unable to provide informed consent. * History of clinically important renal, cardiovascular or neurol. diseases (apart from MS). * Malignancy within the past 2 years. * Cannabinoids taken currently or in previous 30 days. * Positive qualitative urinary test on cannabinoids at screening visit. (In this case a patient will be allowed to repeat the test at a second screening visit later.) * Known hypersensitivity to cannabinoids. * Current drug abuse, including alcohol abuse. * Laboratory parameters outside the following limits: Creatinine \> 3x upper limit of normal Bilirubine \> 3x upper limit of normal Transaminases \> 5 x upper limit of normal * Anticipated immunisations within the 12 weeks of trial participation. * Other problems likely to make participation difficult at the discretion of the neurologist. * Women who are pregnant, lactating or not using adequate contraception. * Participation in other treatment studies currently or within the previous month.