FOSTER CITY (CBS 5) — A Bay Area woman said she lost her sense of taste for more than a week after using a popular alcohol-free mouthwash.

It's one of hundreds of complaints that have been lodged against Crest Pro-Health Complete mouth rinse, which has been on the market since 2005.

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Kate Steeper of Foster City tried the rinse two weeks ago, before bedtime. Steeper told CBS 5 ConsumerWatch, the next morning, "I woke up and I noticed I couldn't taste my breakfast."

She said her tongue felt strange as well. "It felt like when you eat pizza that's too hot, like burning your tongue and then you can't taste anything," Steeper said. The Foster City woman said her sense of taste didn't return to normal until eight days after using the rinse.

The Food and Drug Administration has received about 350 complaints about the mouth rinse. Reviewers on online retail sites such as Amazon have also posted criticisms about the product.

Most of the complaints are about a different side-effect: teeth staining. However, others have complained about the same mouth-numbing effects as Steeper.

Dentist Mark Ryder, director of periodontology at UCSF, said the rinse's active ingredient is antiseptic called cetylpyridimium chloride (CPH). Ryder said studies show CPH is effective. He was also surprised to hear just how long Steeper's taste-loss lasted.

"Sometimes it could last for minute, sometimes it could last for several hours. Some patients do notice that it does change their sense of taste, but their sense of taste does come back," he said.

Crest told CBS 5 ConsumerWatch that the product, "may alter your taste, but it shouldn't be permanent. And it is not a health issue." As far as the staining is concerned, the company said the product can discolor plaque and germs already in the mouth and can be removed through brushing or professional care.

Steeper said Crest needs to do more. "At the very least, they should have a warning label on there," she said.

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Crest's website said the mouthwash does not have a warning because "the active ingredient in Crest Pro-Health Rinse has been recognized as safe and effective by an FDA advisory panel. The label meets current FDA standards."

ConsumerWatch contacted the FDA, which is currently looking into the matter.

Crest added that it does not have plans to put a warning label on the bottles and is willing to offer anyone who doesn't like the mouth rinse a full refund.

Ryder suggests buying a trial-sized bottle of the mouthwash first to see how much you like it and how it affects your mouth and recommends reporting any ill-effects to the FDA.