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The US Food and Drug Administration has issued a warning letter to Dollar Tree for receiving over-the-counter drugs produced by foreign manufacturers that have been found to be adulterated, including acne treatment pads and Assured brand drugs.

The letter – sent earlier this month to Greenbrier International Inc., which does business as Dollar Tree – describes Dollar Tree’s receipt of adulterated drugs from manufacturers and suppliers that had received separate FDA warning letters last year and were placed on “import alert.”

The letter outlines “multiple violations” of manufacturing practices at those contract manufacturers used to produce Dollar Tree’s Assured Brand over-the-counter drugs as well as other drug products sold at Dollar Tree and Family Dollar stores.

Now, in its warning letter to Dollar Tree, the FDA is requesting that the company implement a system to ensure that it does not import adulterated drugs.

“Americans expect and deserve drugs that are safe, effective and that meet our standards for quality. The importation and distribution of drugs and other products from manufacturers that violate federal law is unacceptable,” Donald D. Ashley, director of the Office of Compliance in the FDA’s Center for Drug Evaluation and Research, said in a news release on Thursday.

“In this case, Dollar Tree has the ultimate responsibility to ensure that it does not sell potentially unsafe drugs and other FDA-regulated products to Americans,” he said. “We will remain vigilant in our efforts to protect the U.S. public from companies who put the health of Americans at risk – whether through the manufacturing and distribution of products we regulate or other means.”

In response, the Dollar Tree company, which operates stores under the Dollar Tree and Family Dollar brands, said that it is cooperating with the FDA and plans to meet with the agency.

“We are committed to our customers’ safety and have very robust and rigorous testing programs in place to ensure our third-party manufacturers’ products are safe,” Randy Guiler, vice president of investor relations at Dollar Tree, said in a company statement on Thursday.

“Each of the items referenced in the report are topical, and not ingestible, products. As always, we are cooperating with the US Food and Drug Administration (FDA). We plan to meet with the FDA in the near future and expect that our plans will satisfy their requirements in all regards,” the statement said.

The company has 15 working days to respond to the FDA in writing, the warning letter says, and “failure to promptly correct the violations may result in legal action without further notice including, without limitation, seizure and injunction.”

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The warning letter notes how some of the drug products came from Shanghai Weierya Daily Chemicals Factory and Hangzhou Zhongbo Industrial Company Ltd., which the letter details have shown a pattern of serious violations of the law, such as not testing raw materials or drugs for pathogens and quality.

The FDA encourages health care professionals and consumers to report any adverse events that might have occurred while using over-the-counter drug products from the contract manufacturers.