The prevention of colds and flus with Echinacea for long economy flights

INTERVENTION: Intervention tablets contain 675mg herb equivalent of Echinacea purpurea and 600mg herb equivalent of Echinacea angustifolia. Participants will take 1 tablet twice a day for 2 weeks prior to travel, 2 tablets twice a day when flying, 1 tablet twice a day during their time away. If the participant experiences symptons of a cold or flu, they will take 3 tablets twice a day for a maximum of 4 days before returning to the normal 1 tablet twice a day dose. CONDITION: airline travel related colds, flus and other respiratory disorders PRIMARY OUTCOME: A decrease in travel related colds, flus and other respiratory disorders. SECONDARY OUTCOME: nil INCLUSION CRITERIA: travel via economy class from Australia to Europe or North America travel period is between 2 and 4 weeks Participants must be in good health with no colds in the 2 weeks before they start the trial