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. 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. 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.