Parents in Chatham, N.J., are expressing outrage and concern after a CVS pharmacy mistakenly gave them a drug used to fight cancer instead of fluoride pills for their children's teeth.

The parents who came to the CVS pharmacy on Main Street were actually bringing home tamoxifen - a powerful drug to fight breast cancer.

Somehow, the mix up went on undetected for at least two months and maybe longer.

"It's something that's very disheartening to see that happen and who knows what else they did wrong," said parent Davin Clark.

For its part, CVS said in a statement: "The health and safety of our customers is our highest priority and we are deeply sorry for the mistake that occurred at our Chatham, NJ pharmacy. Beginning last week, we have contacted or have left messages for every family whose child was dispensed a 0.5 mg fluoride prescription from our Chatham location within the past 60 days."

Read entire CVS Statement to ABC News Regarding Drug Mistake

The cause of the mix up is still under investigation.  There have been no reports of documented illnesses as a result of the switch up and it appears the mistake was limited to that New Jersey store.

But if you want to be extra vigilant in your home, there are several websites that can help you identify pills:

http://pillbox.nlm.nih.gov/

http://healthtools.aarp.org/pill-identifier

http://www.rxlist.com/pill-identification-tool/article.htm

http://www.drugs.com/pill_identification.html