Although some people considered Mentos to be gluten free, they are not. Here is the company's reply to the inquiry on the subject:
The only raw material which is derived from wheat is the glucose syrup.
The syrup meets the requirements for “gluten-free goods” as laid down in
the Codex Alimentarius (CODEX STAN 117-1981/ max of 20 mg per kg).
However, nearly all ingredients are derived from agricultural products
and could be processed on equipment that also handles products
containing gluten. Therefore Perfetti Van Melle does not actually claim
that Mentos are gluten-free.