Cough is the most common presenting symptom in primary practice.  Subacute cough is defined as cough persisting for 3 to 8 weeks, and chronic cough as that persisting for more than 8 weeks. Subacute cough is most often self-limited, but chronic cough may provide significant challenges for effective evaluation and management. Nontargeted cough suppressant therapy is rarely effective for chronic cough. However, the difficulty is in determining the cause of cough, since some "etiologies" are syndromes without accurate diagnostic tests. The cause is determined instead by typical historical features, elimination of alternative causes, and response to targeted therapies (therapeutic trials serve as tests). Nonetheless, a careful history, along with selected therapeutic trials and/or diagnostic evaluations performed in a systematic and informed way, may satisfactorily resolve cough in over 90% of cases.