Deaths from asthma are relatively uncommon but have continued to rise worldwide in the past few decades, despite a better understanding of the disease and an increased number of patient medications. This often is attributed to inadequate assessment and treatment of the disease. This article focuses on defining several items that pertain to acute severe asthma. In addition, the pathophysiology and clinical manifestation of acute asthma, as well as current investigational tools, are reviewed. Traditional and nontraditional therapies of acute asthma are discussed. Finally, complications of severe asthma and the long-term outcome are discussed, with appropriate preventive measures stressed strongly.