I don't know if I missed this paper at the time, but apparently Swallowtail larval frass (poop) contains a metabolite from the plants the larvae eat that has anti-colon cancer activity.

https://www.sciencebase.com/science-blog/swallowtail-frass-and-colon-cancer.html

Not to say that cancer patients are going to be fed something from caterpillar poo any time soon, these kinds of discovery are going on all the time and most never reach the clinic. But, a few do, so who knows. The team involved seem to have moved on to other metabolites in the 2025 paper from their lab, so they're pioneering and not necessarily propagating...I could be wrong. It's all fascinating and was the stuff I started out writing about back in the early 90s for New Scientist and Science!