Drugs used to treat high cholesterol may also fight HIV, according to doctors in Spain.
The doctors say further research is needed
They gave six people who were HIV positive statins for one month.
They found that levels of the virus dropped while they were taking the drug. They rose when they stopped taking it.
Writing in the Journal of Experimental Medicine, the doctors said statins could be a new and relatively cheap weapon against the disease.
Millions of people around the world take statins. The drugs are given to people with high cholesterol to reduce their risks of heart disease. They stop the liver from producing cholesterol.
Dr Gustavo del Real and colleagues at the Spanish Council for Scientific Research tested the drugs in their laboratory.
They found that the drugs appeared to stop the HIV virus from infecting healthy cells.
The virus was unable to open up the membrane around the cells. It was also unable to get out of infected cells.
Subsequent tests on mice suggested they may help to slow down the disease.
The doctors say the results of this small-scale trial on patients is promising.
"Our results indicate that statins might be suitable anti-retroviral drugs for more accessible Aids treatment," they wrote.
They said further research is needed to see if statins really could be a new weapon against the disease.
"The data suggest that statins can inhibit HIV-1 replication in chronically infected individuals and support future clinical studies of statins as possible anti-retroviral agents."
Recent studies have suggested that statins could help people with various diseases, ranging from Alzheimer's to cancer.
The UK government recently announced plans to allow patients to buy statins over-the-counter in pharmacies. Up until now, only those with doctor's prescriptions have been allowed to buy them.
Professor Brain Gazzard, director of HIV research at Chelsea and Westminster NHS Trust in London, described the latest findings as interesting.
"Statins do interfere with the ability of HIV to get into the cell," he told BBC News Online.
"Whether or not that translates into a potential treatment remains to be seen. But these findings are interesting."