In the grand tradition of Russia, the trendy "Moscow Mule" drink that's served in a copper cup has a pretty good chance of poisoning you.
In a recent article on both The Washington Post and The Hill, a "Moscow Mule" is actually a fairly acidic drink, with a pH "well below 6.0". The "better call 911" part is that "copper should not come into contact with acidic foods with a pH below 6" because copper will leech into the drink (or food) it comes in contact with.
That mule kick? Copper poisoning! Hee-haw!
"Symptoms of copper poisoning include abdominal pain, diarrhea, vomiting and jaundice. Severe poisoning can cause liver failure and death.”
The solution is pretty simple – drink "Moscow Mules" from "copper mugs lined on the inside with another metal, like nickel or stainless steel."
Better yet, have a Guinness.