Answer
Its registered indication is based on longstanding traditional use; clinical effectiveness has not been demonstrated.
Sources for this answer
- Covonia Catarrh Relief Formula / Natures Aid Herbal Catarrh Relief Formula — Current selected SmPCemc · Summary of Product Characteristics
- UK GovernmentUK Government · Reputable Web
General medicine information. Follow the instructions for your own medicine and speak to a pharmacist or clinician about your individual circumstances.