Despite the significant gains made in the treatment of many cancers over the last few decades, further improvements in survival using traditional chemotherapeutic agents have now begun to plateau. The development of bevacizumab, a monoclonal antibody targeted against the vascular endothelial growth factor, has provided promise for continued gains in survival in the therapy of a variety of cancers, including some previously refractory to traditional chemotherapeutic agents. Although its toxicity profile differs from traditional chemotherapeutic drugs, bevacizumab is not completely without side effects. The mechanisms of its unique toxicities have not yet been fully characterised, and at this time it is not possible to predict which toxicities will be experienced by each individual patient or which population.