https://www.scientificamerican.com/article/heres-what-oetzi-the-iceman-ate-before-he-was-murdered/

A mere 2 hours before his grisly murder about 5,300 years ago, Ötzi the iceman chowed down on some mouthwatering morsels: wild meat from ibex and red deer, cereals from einkorn wheat and—oddly enough—poisonous fern, a new study finds.

It's unclear why Ötzi ate the toxic fern, known as bracken (Pteridium aquilinum). But it's possible that he used the fern to wrap his food, almost like a piece of plastic wrap, and then unintentionally ingested some of the toxic spores the fern left behind, said study co-senior researcher Albert Zink, head of the Eurac Research Institute for Mummy Studies in Bolzano, Italy.