Salivary eosinophil cationic protein (ECP) level has the potential to be an assessment tool for asthma. Its measurement is not well-established and needs standardization. We studied how passive drool (PD) and two commercial devices, Salivette(®) (cotton-based device) and Sorbette(®) (cellulose-cotton-based-device), may affect ECP levels during collection among healthy subjects.