Back in 2003 I published some rules about real world poisons and diseases, called Nature’s Wrath. It is still available from DriveThru, right here. It sold well and received a lot of positive reviews. It still sells a few copies now and then.
Since 5e launched, I’ve been thinking about revising and updating Nature’s Wrath to 5e. Over the past year or so, I’ve spent some time on it. A few 5e poisons have been posted on my Patreon, and I plan to post some more soon.
Currently, the next project in the pipeline is Nature’s Wrath: Poisons (5e), which covers all the toxic plants that exist in our world. It also has rules for using skills and tools to make medicines from some of these plants. When that is finished, I’ll do a separate PDF for the diseases. I’m also considering doing one for animal based poisons, since those get short shrift in the core rules. When all of that is done, I may put it all together in a kickstarter with some poison oriented adventures as well.