Typical asthmatic reactions after exposure to common or occupational allergens have been classified as isolsted immediate, early late, late and dual reactions by Pepys and Hutchcroft. Atypical reactions including progressive, square waved and prolonged immediate reactions can also occur. In this study we compared the results of the bronchoprovocation test to the common inhalant allergens and specific reagents in the adult bronchial asthms patients. This study included 181 cases who showed positive response to inhalant challenges with Dermatophagoides farinae, cat hair, pollens, toluene diisocyanate(TDI) and aspirin (lysine aspirin) from January 1992 to June 1995. The three groups of sensitizing agents were common inhalant allergens(D. farinae, cat hair, and pollen), TDI as occupational sensitizing agent and aspirin(lysine aspirin). 1. Typical patt,erns(early, dual, late and early late) were found mainly in the group of challenge positive with common inhalant allergens, 133/146(91.1%). Early responses were in 70 of 146 cases(48.0% ), dual reponse in 38/146(26.0% ), late reponse in 25/146(17. 1%). Atypical patterns occur in 13/146 instances(8.9%). Nine of 146(6.2%) reactions were squsre waved. Four of 146(2.7%) reactions were prolonged immediate. 2. In the TDI challenge tests, typical patterns occur in 14/18 instances(77.7% ) and atypical patterns were in 4/18(22.3% ). 3. In the aspirin(lysine aspirin) challenge test, typical patterns occur in 11/17 instances (64.8% ). Six of 17(35.2% ) were atypical. 4. Atypical reactions tended to increase in TDI or aspirin challenge cases comparing to common inhalant allergen tests, although the differences were not statistically significant among these groups(p=0.08). These findings suggest that asthma due to TDI or aspirin has the different pathophysiology from asthma with common inhalant allergens. The research to clarify the mechanism of sensitization is in need.