The gel, called "Pro-2000," is part of a large clinical trial.
This is the first time a gel like this has been shown to work.
Pro-2000 works by blocking HIV from entering cells.
Researchers say it was found to be safe overall, and effective in 30-percent of women studied.
Did you know that Americans spend more than 20 billion dollars each year on vitamin supplements?
Well, new research says they may not be helping.
Experts studied data from over 160,000 women.
They found no difference in cancer rates, heart disease or death between women who took supplements and those who did not.
Experts say food may be the best way a woman can lower her risk for disease, and that multi-vitamins are not magic bullets that automatically prevent disease.