Knowledge of asthma and its treatment were evaluated in a survey of 1,000 asthmatics using a self-questionnaire with closed questions. As far as the disease was concerned, 87.4% of patients knew that the bronchi were the pathological organ and 70.6% that the disease persisted between attacks. Overall knowledge of the disease (pathological organ, persistence of the disease between attacks, chronic inflammation associated with acute bronchoconstriction) was adequate in only 25.6% of patients. It was associated with the educational level [higher > primary; p = 0.001], the grade of asthma [severe > mild; p = 0.007] and the number of medicines inhaled [(n > 3) > (N < 2); p = 0.001)]. As far as medicines were concerned, knowledge of their mechanisms of action varied according to therapeutic groups: antiallergics [78.6%], antibiotics [77.7%], antihistamines [74.5%], LA beta2-mimetics [45.9%], theophylline [31.9%], corticosteroids [31.7%], beta2-mimetics [24.8%]. No factor was statistically correlated with greater familiarity. However, only 7.2% of patients treated with metered-dose aerosols expressed handling problems and 78.8% of asthmatics questioned felt that they were sufficiently informed about their disease and its treatment. Information and education thus remain a priority in the management of asthma.