Oil of oregano is one of my go-to herbs for supporting the immune system because of its antimicrobial properties. Make sure you pick one up with at least 75% carvecrol, the active ingredient, and be cautious of how much you use for your first time as it’s HOT – wash your hands thoroughly with soap and water after use and avoid contact with eyes (and keep out of reach of children)!
Tips for maintaing health while travelling are available here. Read this post to find out the difference between cold, flu's and allergies. For information about preventing allergies, check out this post. Tips for preventing colds and flu's can be found here and about preventing the spread of colds and flu's here.