Is guifenesen good to use with asthma?

Guaifenesin: Guaifenesin is an expectorant. It helps loosen congestion in your chest and throat, making it easier to cough out through your mouth. Its effects maybe more theoretical than practical. Drinking adequate fluids will produce the same effect. I hate to leave the decision for you to make for yourself but , honestly, i would rather have you push more fluids.

See below: Guaifenesin is a medicine in the class called expectorants. They are used to thin mucous in the air passages to make it easier to cough out the mucous and clear the possible plugging due to the mucous and clear the airways. It won't help asthma directly but may help to loosen the mucous that may be blocking/closing some of the airways.