Laser polarised (hyperpolarised) 129Xe offers a new potential way for assessment of cerebral blood flow (CBF) by nuclear magnetic resonance (NMR). We present the basic physical principles underlying noble gases'laser polarisation. Distinguishing characteristics of 129Xe NMR properties as well as theoretical basis for CBF measurement using laser polarised 129Xe are emphasized. Recent results are briefly presented and potential applications as well as current limitations of 129Xe in CBF studies are discussed.