Cocktail lovers could be getting more than just a buzz sipping a Moscow Mule in a copper mug.
Iowa’s Alcohol Beverages Division found that the mug in which the drink is traditionally served may cause copper poisoning.
In Iowa, the metal is prohibited from coming in direct contact with foods or drinks that have a pH below 6.0 — such as vinegar, fruit juice and wine.
That’s because copper can seep into the drink or food if it comes in contact with acidic foods.
Moscow Mules, which contain vodka, lime juice, ginger beer, fall well below that critical pH, according to a bulletin by the under the federal Food and Drug Administration’s Model Food Code.
It warns against enjoying the refreshing cocktail in copper mugs — and suggests that the mugs be lined with nickel or stainless steel.
Copper poisoning can cause abdominal pain, diarrhea, vomiting and jaundice.