text: what is the difference between a mucolytic and expectorant?   a mucolytic is a agent that brings about the lysis of the cough or in simple words u can say that it makes a thick cough more watery or less thick a expectorant is a agent which helps you in bringing out the cough that is inside ur chest or u can say that it it makes u cough a bit so that u can spitout the cough that is collected inside it is good to take a combination of the 2 to get relief from a bad chesty cough that u have