Devices which produce an aerosol (see under INHALANTS) by blowing air or oxygen through a solution of a drug. Many inhaled drugs such as SALBUTAMOL, ipratropium and CORTICOSTEROIDS such as beclomethasone can be given in this way. The have the advantage over a Metered Dose Inhaler (MDI) that no special effort is required to coordinate breathing, and a nebuliser allows a much greater volume of the drug to be delivered to where it is needed (the airways) compared with that of MDIs. The safety profile of anti-asthmatic drugs such as salbutamol is extremely high and the high doses necessarily given by nebulisation are generally well-tolerated.