If you’ve ever ordered a Moscow Mule, it was probably served to you in one of those copper mugs to keep the drink as ice cold as possible. But a new advisory from the Iowa Alcohol Beverages Division warns that those mugs can present some health risks, although in reality your likelihood of getting copper poisoning are pretty low.

The advisory bulletin warns that copper shouldn’t come in direct contact with food or beverages as it might leach out and poison people. However, experts estimate you would have to be drinking Moscow Mules with every meal of every day for 25 years to get copper poisoning, according to a report from Business Insider. If you’re drinking that much, you’ve got much bigger problems than copper poisoning.

So as long as you only drink Moscow Mules occasionally, it should be perfectly find to drink from those copper mugs.

“The purpose of this bulletin is to advise licensees and permittees selling and serving alcoholic beverages in copper mugs of the applicable federal guidance and state regulations regarding the use of copper and copper alloys in contact with food and beverages,” the advisory states. “The recent popularity of Moscow Mules, an alcoholic cocktail typically served in a copper mug, has led to inquiries regarding the safe use of copper mugs and this beverage. The use of copper and copper alloys as a food contact surface is limited in Iowa. Iowa, as well as many other states, has adopted the federal Food and Drug Administration’s Model Food Code, which prohibits copper from coming into direct contact with foods that have a pH below 6.0. Examples of foods with a pH below 6.0 include vinegar, fruit juice, or wine.”