Many chemical irritants have yet to be elucidated, but known culprits include calcium oxalate, protoanemonin, isothiocyanates, bromelain, diterpene esters, alkaloids, and other chemical irritants ...

The vast majority of CICD reactions, however, are caused by one of seven basic irritant groups: calcium oxalate, protoanemonin, isothiocyanates, diterpene esters, bromelain, and alkaloids.