With their colorful egg-shaped containers, palatable price points ($2.99) and assorted fruity and sweet scents, EOS (which stands for Evolution of Smooth) lip balms have been flying off of store shelves for several years. The lip balms have also become the darlings of many A-list celebrities including Britney Spears and Kim Kardashian.

But now a new class-action lawsuit alleges that these balms may do more harm than good.  Many people have reportedly gotten severe rashes, hives, and blisters after using EOS products. How many people are we talking about? Potentially hundreds of thousands.

According to multiple media reports, the lawsuit was filed against EOS after a plaintiff had a severe reaction to the lip balm that lasted more than 10 days class. In addition to seeking damages, the lawsuit also calls for corrective advertising.

The EOS Facebook page is lighting up with reports of similar reactions. The company is asking individuals to detail their experiences in an email to info@evolutionofsmooth.com. “Please know that the health and well-being of our customers is our top priority. We are very sorry to hear of your experience and we want to do what we can to make things right for you,” the Facebook page says over and over again in response to claims.

Joshua Zeichner, MD, the Director of Cosmetic and Clinical Research in Dermatology at Mt. Sinai Hospital in New York City, says that allergic reactions and irritation to personal care products are not infrequent.  He couldn't comment on the specific cases in the EOS lawsuit, but did say that such allergies commonly develop to preservatives, fragrances, and dyes. “ In the event of a reaction (eg. burning, stinging, peeling, redness), the product should be discontinued immediately,” he says.  “Cortisone creams can help cool down inflammation.  If this is a recurring problem, patch testing in the office may help uncover what the culprit is.”