Eucalyptus is a fast-growing evergreen tree native to Australia. As an ingredient in many products, it is used to reduce symptoms of coughs, colds, and congestion.Chinese, Indian Ayurvedic, Greek, and other European styles of medicine have incorporated it into the treatment of a range of conditions for thousands of years.

Eucalyptus features in a range of preparations to relieve symptoms of the common cold, for example, cough lozenges and inhalants.

Herbal remedies recommend using fresh leaves in a gargle to relieve a sore throat, sinusitis, and bronchitis. Also, eucalyptus oil vapor appears to act as a decongestant when inhaled. It is a popular home remedy for colds and bronchitis.

It may act as an expectorant for loosening phlegm and easing congestion. A number of cough medications include eucalyptus oil, including Vicks VapoRub.

Researchers have called for further studies to clarify the possible therapeutic role of eucalyptus leaf extract in the treatment of respiratory tract infection.