Nasal administration of medicines with local effect is the natural choice for the treatment of acute and chronic topical nasal disorders such as allergic rhinitis, nasal congestion and nasal infections. At the same time, it is an attractive route for certain active substances with a systemic effect. Large absorption surface, low enzymatic activity and high vascularisation and permeability of nasal mucosa may provide high rate of drug absorption, relatively high blood concentrations and therapeutic effect shortly after nasal administration. Effectiveness of nasally administered drug depends on nasal physiology and physicochemical properties of drug and formulation. Properties of nasal formulation and method of its administration should be adjusted to anatomical and physiological features of the nasal cavity. Nasal formulations should not interfere with the physiological function of the nose and mucociliary apparatus, which clears foreign particles and microorganisms from the airways thus playing an important role in respiratory defence mechanism. Current investigations on nasal drug delivery are directed towards development of innovative nasal delivery systems able to increase bioavailability of systemically acting drugs. The final aim is to replace invasive intravenous drug delivery with more convenient nasal delivery, which will enable self-medication resulting in patient and health care system benefits. At the same time significant efforts are made to develop nasal delivery systems able to potentiate direct nose to brain delivery of the drug. Success in this investigation area would represent a turning point in the treatment of neurological diseases.