BACKGROUND: Management of acute sore throat poses a significant burden on UK general practices, with almost 10% of registered patients attending their GP with sore throat every year. Nearly half of all patients presenting with acute sore throat are treated with antibiotics, despite their limited effect. In a recent systematic review we demonstrated that a single dose of steroids reduced the severity and time to resolution of sore throat. However, all of the trials included looked at the use of steroids alongside antibiotics and only one was in a primary care setting. This trial aims to assess the efficacy and cost-effectiveness of a single oral dose of corticosteroids on symptoms of sore throat in patients receiving either a delayed antibiotic prescription or no antibiotics at all in UK primary care. METHODS/DESIGN: A double-blind, two arm, randomized, placebo controlled trial in adults (≥ 18 years of age) presenting to primary care with acute sore throat (