By Brigitte Mars, for healthshop.com

Tea tree oil's antibacterial properties have been documented by researchers since the 1920s. It was a standard ingredient in Australian first aid kits until World War II. At home, tea tree oil can be applied to disinfect cuts, pimples, and fungal infections.

Gargling with two drops in a glass of warm water improves sore throats and a few drops rubbed on the chest or back helps relieve nasal congestion. It is one of the few essential oils that can be applied directly to the skin without dilution.