"Xiao" refers to the sound in the throat, with phlegm sounds whether the mouth is open or closed, while "chuan" refers to breathing, with rapid and urgent breaths, more rising and less falling. During the stage of attack, "Xiao" is often accompanied by panting, but "chuan" does not necessarily accompany "Xiao". It is customary to collectively refer to them as asthma, but in reality, there is a distinction.