Paracetamol is recommended for the routine treatment of fever in influenza; however in animals, the treatment of fever in experimental influenza infection increases mortality. In humans, paracetamol increases the duration of the illness in some viral infections. The objective of this study is to test whether the use of paracetamol to treat fever results in longer viral shedding or more prolonged symptoms in natural influenza infection. It will involve screening 160 subjects with influenza like illness, to enable 80 subjects with confirmed influenza to be randomly assigned to receive either paracetamol 4 times a day or identical placebo for five days. Daily swabs and symptom scores will test for viral clearance and resolution of the illness. If paracetamol is shown to prolong viral infection or worsen symptoms, the results of this study could have major implications for the routine management of influenza.