Undertaking peripheral intravenous (IV) cannulations and the management of cannulae are associated with the risk of blood leakage or spillage and blood exposure. Open cannulae are the most common type of peripheral IV cannulae used in the UK. However, closed cannulae, also known as blood-control cannulae, have the potential to reduce the risk of needlestick injury, blood leakage and blood exposure during cannulation, as well as to increase dwell time and patient comfort. Closed cannulae may also reduce the time taken to perform cannulation. This article explains the differences between open cannulae and closed cannulae. It reviews the current use of open cannulae and the risks of blood exposure and how these can be reduced. The benefits of using closed cannulae are also described.