some species contain a toxic chemical (pederin) in their hemolymph which causes contact dermatitis in humans, usually as a result of slapping the beetle and crushing it against exposed skin. The affected area becomes red, swollen, and itchy, causing the skin to peel when scratched.(3)
Extracts of Paederus
beetles have been used by the Chinese since at least 739 AD in the medicinal treatment of boils, nasal polyps, and ringworm.