BMJ Group Medical Reference
These medicines are meant to stop you coughing. Some people with a cough find them useful to get a good night's sleep.  But we don't know if they help the symptoms of acute bronchitis.
A large review of the research found mixed results on cough suppressants.  A few studies were positive, and others were negative. Overall, the research doesn't show clearly whether cough suppressants work or not.
Cough suppressants that you can buy without a prescription often contain: 
If a cough suppressant helps you cough less, you may cough up less mucus. This could be harmful if you have certain underlying problems, such as chronic bronchitis. 
Many cough and cold remedies aren’t recommended for children under 2. If you're in any doubt whether a product is suitable, talk to your doctor or pharmacist. To find out more, read Treating coughs and colds in children.
Some syrupy cough medicines aim to stop you coughing by coating your throat, which may feel soothing. One example is simple linctus. You might find these treatments helpful if you have a dry, irritating cough. 
Your doctor may say that you have chronic bronchitis if you have a cough that brings up phlegm, if it lasts for three months or more, and you have had it twice in two years. Smoking is a common cause of chronic bronchitis.
For more terms related to Bronchitis
For references related to Bronchitis click here