Maintaining oral health in the critically ill patient is imperative in reducing the risk of nosocomial infections and improving patient comfort and discharge outcomes. Critically ill patients are at great risk for poor oral health as many are elderly, undernourished, dehydrated, immunosuppressed, have a smoking or alcohol history, are intubated or on high-flow oxygen, and are unable to mechanically remove dental plaque. Many modalities for delivering oral care have been reported in the literature. The use of the toothbrush in the mechanical removal of plaque, even in the intubated patient, has been proven to be superior to the swab. Brushing of the gums in edentulous patients is of benefit. Although electric toothbrushes are preferable, their cost, size and the potential for cross-infection limits their use. Chlorhexidine has long been the gold standard for mouthwashes and provides up to 24 hours of antimicrobial activity; therefore infrequent applications are adequate. Sodium bicarbonate and hydrogen peroxide are of limited use due to lack of convincing evidence regarding their safety and antimicrobial effects in the critically ill population. Saliva stimulants or substitutes including lemon and glycerine are also inappropriate for moistening the oral cavity in the critically ill patient. Regular oral assessment and individualized oral care, along with the use of a standardised protocol for oral care (incorporating proven modalities) is vital for optimal oral care in the critically ill patient.