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In a study of bronchial responsiveness to aerosols of graded histamine doses (0.003 to 1.0 mg/ml) in 2 normal, 19 bronchial asthma and 10 COPD patients; it was seen that by FEV 20% criterion 6(32%) asthmatic 3(30%) COPD patients responded. By MEFR 0.25-0.75: 25% criterion 9(47%) asthmatic and 8(80%) COPD had responded to 1 mg concentration. The declines by FVC were similar but criteria of PEF or Raw were less helpful. While more asthmatic patients responded at lower doses of histamine, the differences were not significant. Thus asthmatic presentations in the city may be nonallergic in origin and cause may be similar to that in subjects with symptoms of chronic bronchitis.