"Pharmacologic Study of Oseltamivir in Healthy Volunteers" is a Phase I study in which 8 to 32 adult healthy Thai volunteers will be randomized to one of four drug doses and regimens within each of 4 visits. The study is being conducted at the Bangkok Hospital of Tropical Diseases Research Unit, Faculty of Tropical Medicine, and commenced enrolling healthy volunteers on 23 November 2006. The duration of the study is expected to be approximately four months. The goals of this study are to assess the use of loading dose oseltamivir and the concomitant use of probenecid and to characterize the pharmacokinetic properties of oseltamivir in Thai subjects.