I also use Thieves oil on a regular basis. It is great for anything related to colds and flu, viruses and bacteria. The range also includes cleaning products infused with the Thieves blend.
I use Thieves oil in my diffuser when anyone in the family is starting to feel cold/flu symptoms. It is certainly an oil worth having as I have not been sick for a long time and my 12 yr old son had the start of a cold, we diffused Thieves in his room and he was better by the morning.