Treatment of uncomplicated acute illness due to influenza infection in adults patients and patients who weigh more than 40 kg who have been symptomatic for no more than 2 days. - Post exposure prevention in adults and patients who weight more the 40 kg following contact with a clinically diagnosed influenza case when influenza virus is circulating in the community. - The appropriate use of Tamiflu for prevention of influenza should be determined on a case by case basis by the circumstances and the population requiring protection. In exceptional situations (e.g. in case of a mismatch between the circulating and vaccine virus strains and a pandemic situation) seasonal prevention could be considered in adults patients and patients who weigh more than 40 kg.