The nasal provocation test (NPT) is a simple procedure with high specificity and sensitivity that is used in the investigation of allergic and nonallergic diseases. Uniform standards are of particular importance in the clinical setting and for the comparability of clinical and basic allergy research. These standards should cover the composition, dosage and pharmacological formulation of provocative substances (e.g. allergen extracts), the necessity of titration, allergen application methods and the evaluation criteria for a positive NPT reaction. Detection of various mediators and cytokines in nasal discharge can be very useful in the late phase reactions. NPT finds specific applications in studies of local IgE secretion in the nasal mucosa, the diagnosis of analgesic intolerance and in assessments of the efficacy of specific immunotherapies. Additional parameters warranting further evaluation include provocation with cold dry air in nasal hyperreactivity patients and nasal nitric oxide formation. Determination of nasal blood flow during NPT provides an additional clinical parameter.