Answer
Dextromethorphan in Covonia Original Bronchial Balsam Syrup acts centrally as a non-narcotic cough suppressant, raising the threshold for coughing.
Sources for this answer
- Covonia Original Bronchial Balsam SyrupThornton & Ross Ltd · emc · SmPC §5.1 Pharmacodynamic properties · Version 8Document updated
Sources checked