INTRODUCTION: Airway hyperresponsiveness (AHR) is a key feature of asthma and can be assessed by the use of bronchial provocation tests. A test using inhaled dry powder mannitol for diagnosing asthma is now regulatory approved in 20 countries. AREAS COVERED: This paper reviews the literature on inhaled mannitol from the first publication in 1997 until present (October 2011). It discusses the current knowledge on the clinical usefulness as a tool for diagnosing and managing asthma. EXPERT OPINION: Inhaled mannitol can be regarded as a safe, standardized, specific, but less sensitive, tool for the diagnosis of asthma in both children and adults. Discomfort, in terms of cough, during the test occurs in 85.3% of subjects, but rarely (1.3%) leads to discontinuation. Headache (6.1%), pharyngolaryngeal pain (2.6%) and cough (1.3%) are the most frequent adverse events that occur on the day of the test. The test holds several advantages compared with existing tests; there is no need for additional equipment (i.e., a nebulizer) besides a spirometer; it requires no cleaning and has only one standard operating protocol. In a new study using mannitol for monitoring mild and moderate persistent asthma in primary care, the number of mild exacerbations was reduced.