Rose-hips could offer a cheap and effective way of treating debilitating rheumatoid arthritis, research from Germany and Denmark has suggested.
Rose-hips could help some of the UK's 400,000 sufferers
Seventy-four sufferers, mostly females, took part in the six-month trial.
Just under half took the rose-hip remedy LitoZin while the others took a placebo. Both groups continued to take their usual medication.
Activity among the first group improved by 20-25%, according to results presented at the annual Eular meeting.
The number of joints causing pain or discomfort fell by 40%, but did not change for those treated with the dummy.
"I think we were all surprised to see such meaningful results," said Professor Stefan Willich from the Charite University Medical Centre in Berlin, who conducted the German arm of the study.
"Rheumatoid arthritis is one of the most difficult conditions I'm aware of. It's a tough disease, which makes it all the more remarkable to find such beneficial effects from this remedy."
Experts now want to conduct more extensive trials to see if the results are confirmed.
An estimated 400,000 people in the UK suffer from rheumatoid arthritis, a potentially crippling condition which occurs when the immune system attacks the joints.
It causes swelling and damage of cartilage and bone.
Anti-TNF (anti-tumour necrosis factor alpha) medication and the latest "smart" drugs which target different parts of the immune system are becoming available, but they are expensive, and there have already been complaints of "postcode lottery" access.
One month's supply of the LitoZin supplement costs around £20.
It is already available at high-street chemists as it is widely used by patients with osteo-arthritis, a less debilitating condition caused by general wear and tear.
Researchers are unclear as to why exactly rose-hip has this effect, but the supplement appears to have both anti-inflammatory and anti-oxidant properties.
One of the key active ingredients in LitoZin - a type of sugary fatty acid called GOPO - was hailed by scientists involved in the research as a "plant version of fish oil", the supplement believed to have a host of health benefits.
Professor Kaj Winther, who ran the Danish part of the study, said the supplement could be used as an interim treatment to postpone the day the patient needed to move on to the more expensive drugs.
Professor Alan Silman, the medical director of the Arthritis Research Campaign, said that if rose-hips were shown to have only limited side effects they could be a useful adjunct to conventional drug treatment for people with rheumatoid arthritis.
However, he added that the results of the study had to be treated with some caution as the patients were given rose-hip extract to supplement their normal therapy.
Larger studies over a longer period were needed for the results of the small study to be confirmed, he said.