Patients attending the department with cellulitis who are suitable for oral antibiotic treatment will be enrolled into this study. A separate doctor will re-examine at least 10% of study participants in order to reduce bias. A set of physical signs and symptoms will be recorded from each patient in order to determine which ones are associated with them "failing" prescribed oral treatment. A study investigator will then phone the patient after 14 days to see whether they are better or whether they required intravenous antibiotics to get better.