The oral cavity is an important source of bacteraemia for patients with malignancies. Many studies have shown oral infections can lead to life-threatening sepsis in immunosuppressed patients undergoing cancer therapy. However, knowledge in this area is limited as it is based mostly on small patient studies with no large multicenter trials. Clinical practice guidelines are needed to establish evidence-based treatment protocols for oral infections to prevent sepsis of oral origin. Close cooperation between oncology and oral health units is important to maintain oral health and treat potential infection foci before immunosuppressive therapy.