Heterobasidiomycetes, including the jelly, rust and smut fungi; Previously the entire Basidiomycota were called Basidiomycetes, an invalid class level name coined in 1959 as a counterpart to the Ascomycetes, when neither of these taxa were recognized as divisions.
Too much of anything is bad is general rule of thumb. I found several articles which favour eating peppermint and detail side effects of over consumption. But in general there are some side effects of eating altoids and other mint gums. Mouth sores, headaches, stomach burns are few of them. Check out following links for more information. peppermint: Uses, Side Effects, Interactions and Warnings.
Peppermint is often cited as a helpful fix for nausea and upset stomach because the menthol in its leaves is a natural analgesic. Try brewing a cup of peppermint or spearmint tea, sniffing peppermint extract, sucking on a minty candy, or even chewing on the leaves themselves.