[quote=@catchamber] I'd love to see you explain how to produce all of that in a language you don't know, and get it running within your now shortened lifespan, all without googling anything. [/quote] Given that [url=https://www.newscientist.com/article/2123669-neanderthals-may-have-medicated-with-penicillin-and-painkillers/]research into neanderthal dental records reveal they ate compounds that contain Penicillium chrysogenum[/url] it wouldn't be entirely difficult to demonstrate how to further refine a product they were probably consuming anyways. And if this were a preped situation then on your end it wouldn't be much work to identify the natural sources and then go on ahead after learning Cherokee, Cree, Iroquois, or any of the Anishinaabe languages (most were regionally mutually intelligible so it wouldn't be totally alienating if you were ready to appear in Illinois but ended up in pre-Colombian Canada. But on disease: that wouldn't be an issue. As a product of generations of local evolution and of evolution from European stock we'd have a pretty strong natural resistance to any disease from the time. We'd be most at threat of cholera or the typical urban-center diseases that flared up on a regular basis in Europe at the time. But proposing we're going to 15th century America and not Europe: the Americas would be devoid of any significant infectious diseases, unlike Europe. Key may be riskier to the natives than they are to him if he's carrying any non-symptomatic disease, or takes a horse. Those diseases that would be most at risk to him then would be those he'd be at risk now if he were to take a walk in the woods. Even then he'd be in the clear if he wore long socks and covered himself in mud.