A study by scientists in Bath shows cannabis can significantly ease the pain of rheumatoid arthritis.
The authors now want to conduct a larger trial to back up their findings
Taken in medicine form, the class C drug was shown to improve the pain of movement, pain at rest, quality of sleep and ease inflammation.
The researchers say the element of the drug which creates a potential "high" is an essential therapeutic component and cannot be removed.
The authors now want to conduct a larger trial to back up their findings.
Fifty-six patients took part in the 49-day trial led by David Blake, professor of bone and joint medicine at the Royal National Hospital for Rheumatic Diseases, Bath, and the University of Bath.
Cannabis trial results
On a scale of 0-10 for pain on movement, with 0 equalling no pain, those sufferers taking the CBM reduced their pain from 7 to 4.8
Those on the placebo cut their pain from 6.7 to 5.3
Regarding quality of sleep, those on the CBM reduced their pain from 5.7 to 3.4, while the placebo group moved from 5.8 to 4.6
On a scale of 0-100 for intensity of pain at present, patients taking CBM reduced pain from 48 to 33, while those on the placebo stayed the same at 50
Of those, 31 were given a cannabis-based medicine (CBM) - brand name Sativex - while 27 received a placebo.
Sativex uses two key components from a cannabis plant which are shown to have anti-inflammatory properties.
Patients took the medicine in the evening via a mouth spray and started with one dose, gradually building up to a maximum of six doses.
The results of the trial, published in the medical journal Rheumatology show that the CBM produced "statistically significant" results.