A study was performed to assess the time between drug intake and drug induced hypersensitivity reaction for patients sensitive to nonsteroidal antiinflammatory drugs (NSAID) in clinical patient history and after oral provocation tests. Drug hypersensitivity ENDA questionnaires were filled for the patients with suspected sensitivity to NSAID. Oral provocation tests were performed with suspected NSAID according to the ENDA/EAACI recommendations. There were 76 patients with history of hypersensitivity reactions after use of NSAID enrolled in the study. Recorded were 154 hypersensitivity reactions to NSAID in the clinical history. In the clinical history median time of immediate reactions (76 cases, 81%) between drug intake and bronchospasm was 20 minutes [15-30 minutes]. Median time of nonimmediate reactions (18 cases, 19%) was 120 minutes [120-390 minutes]. There were 50 oral provocation tests performed, 14 of them (28%) were positive. Median time between drug intake and immediate reactions (8; 57% of cases) was 22.5 minutes [20-30 minutes] and median time of nonimmediate reactions (6; 43% of cases) was 167.5 minutes [125-206.25 minutes]. Time delay between drug intake and bronchospasm in the clinical history and after oral provocation test was not statistically different.