[Ductapemaster]

I helped my mom transplant a large agave plant and got in contact with a considerable amount of sap in the process — it's extremely uncomfortable and it took probably 3 months for the resulting rash to go away on my inner arms.

The irritation comes from raphides [0], which are sharp calcium oxalate crystals that get into your skin. Definitely something to avoid if you can! I have no idea how folks work with bare skin around those plants...

Interestingly, pineapples and kiwis have raphides in them as well, so if your mouth feels cut up after eating some, that is why.

[0] https://en.wikipedia.org/wiki/Raphide

[admash]

The “cut up” feeling that can occur after eating kiwi or pineapple is more likely to be caused by the natural proteases present in the raw fruit (actinidain and bromelain, respectively) as the “cut up” feeling generally does not occur in cooked or canned fruit due to denaturing of the protein proteases. Raphides, which are sharp, insoluble calcium oxalate crystals, are generally not destroyed by boiling (as stated in your link) as so would still be present in the cooked fruit, suggesting that they are unlikely to be responsible for the “cut up” sensation.