Guaifenesin + Dextromethorphan Hydrobromide + Bromhexine is a combination of three medicines: Guaifenesin, dextromethorphan and bromhexine which relieve dry cough. Guaifenesin is an expectorant which decreases the stickiness of mucus (phlegm) and helps in its removal from the airways. Dextromethorphan is a cough suppressant that relieves cough by reducing the activity of cough centre in the brain. Bromhexine is a mucolytic which thins and loosens mucus (phlegm), making it easier to cough out.