Bro-zedex Syrup contains Bromhexine 4mg Guaifenesin 50mg Menthol 2.5mg Terbutaline 1.25mg. Bromhexine is a mucolytic which thins and loosens mucus (phlegm) making it easier to cough out. Guaifenesin is an expectorant which works by decreasing the stickiness of airway secretions and helps in their removal from the airways. Menthol is an organic compound which produces a sensation of coolness and relieves minor throat irritation. Terbutaline is a bronchodilator which relax the muscles in the airways and widen the airways.Together they make breathing easier.