The data on the effectiveness of mucolytic and expectorant drugs in the treatment of patients with chronic obstructive bronchitis are controversial. A lot of studies have established that acetylcysteine has mucolytic and antioxidant action, leading to a decrease in the frequency of exacerbations. The expectorant drugs haven’t been sufficiently used in the treatment of patients with chronic obstructive bronchitis. Hyper secretion of mucus is one of the main factors contributing to the restriction of air flow while breathing in these patients. In this clinical study 120 patients with the exacerbation of chronic obstructive bronchitis have been involved. They have been divided into four groups. The first group (n = 31) has received a standard treatment along with acetylcysteine (200 mg three times per day). The second group (n = 29) has taken a standard treatment along with a dry extract of ivy leaves (50.4 mg per day). The third group (n = 30) has received a standard treatment along with acetylcysteine and dry extract of ivy leaves. The fourth group (n = 30) has taken only a standard treatment (salbutamol amoxicillin/clavulanic acid). The patients have been examined before and after a 10-day treatment. Before and after the treatment the character, viscosity and adhesion of the sputum have been examined as well. The study has found that the use of acetylcysteine, dry extract of ivy leaves or their combination in the treatment of the exacerbations of chronic obstructive bronchitis significantly reduces the adhesion and viscosity of sputum, the fact that contributes to the effective expectoration. The best effect has been achieved through the administration of acetylcysteine and, especially, by its combination with dry extract of ivy leaves.