Complications of Acute Bacterial Rhinosinusitis (ABRS) are rare (with an incidence in developed countries 1: 12 000 for the paediatric group and 1: 32 000 for the adult group), life-threatening and can present a diagnostic challenge. Haematologic spread can cause a complication far from the original infection site, which presents difficulty diagnosing ABRS. A finding of bacteria of the Streptococcus Anginosus group in ABRS patients should raise suspicion of secondary complications. Orbital complications of ABRS is an indication for emergency CT scan in order to differentiate between post-and preseptal orbital complications. The latter is important in making a decision about surgical treatment. The treatment of ABRS complications consists of emergency drainage and continuous irrigation of the infected sinus, management of the complication itself and antibiotic treatment.