Frances Rosario bought her daughter the breakfast burrito in an Atlanta branch, but found the piece of jewellery in the egg.
The McDonald's in question gave no explanation for the nose ring, and when Rosario complained, she was "rudely rebuffed", reports CBS Atlanta.
Rosario recalled: "I turned it and I see this piece of jewellery sticking out. I'm like, 'What the heck is this?'
"My concern was that if something happened and she had swallowed it.
"For now, I'm going to stay back from McDonald's for a little while."
Employee guidelines at McDonald's state that large loop earrings and visible body piercing are forbidden, apart from one small earring in each ear and a small stud nose piercing.
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