Millions of women who suffer from vaginal yeast infections will be able to skip a visit to the doctor and go straight to the pharmacy for relief, the Food and Drug Administration announced yesterday.

The FDA approved the first over-the-counter drug to treat these annoying infections, which afflict three-fourths of all women at least once in their lifetimes. About 22 million cases are reported annually.

The drug, clotrimazole, has been used safely for more than a decade and is "highly effective and carries a minimal risk," said Carl C. Peck, director of the FDA's Center for Drug Evaluation and Research. The agency said the decision would take effect immediately.

"The FDA has concluded that the switch of this drug to non-prescription sale will benefit women, especially those who are subject to recurring infections," Peck said.

Cindy Pearson, program director of the National Women's Health Network, said the FDA's action was good news for many women, who will be able to get faster, cheaper treatment for a common condition.

"Everyone's delighted," said Pearson, whose health policy advocacy group testified in favor of the change before an FDA advisory committee.

Clotrimazole, which is sold as a cream or vaginal suppository by Schering-Plough HealthCare Products under the trade name Gyne-Lotrimin, costs about $25 for a seven-day course of treatment when it is prescribed. The over-the-counter price will be in the range of $17 to $18, said company spokesman Doug Petkus.

Because the symptoms of a yeast infection can resemble those of some sexually transmitted diseases, labeling on the drug's package will advise: "If this is the first time you are suffering from vaginal itch and discomfort, please consult your physician."

Women who have previously had a yeast infection diagnosed by a health practitioner are familiar with the symptoms: itching and burning, often with a white or yellow discharge and soreness. These women can safely treat themselves "without the inconvenience and expense of going back to the doctor," Peck said.

Vaginal yeast infection, or candidiasis, is an overgrowth of a naturally occurring fungus called candida. The overabundance occurs when the body's natural balance of bacteria is upset. This often occurs when a woman is taking antibiotics or birth control pills. Diabetics are at greater risk of recurring infections, and warm weather can also be a factor.

In rare cases, clotrimazole has caused allergic reactions, including burning and a rash, abdominal cramps and bloating. Pregnant women are advised to use the product under a physician's supervision.