Beclometasone crystals. Coloured scanning electron micrograph (SEM) of crystals of the corticosteroid beclometasone dipropionate (previously beclomethasone dipropionate). Beclometasone is used to treat asthma by decreasing inflammation in the lungs. It is administered through an inhaler and is absorbed into the cells of the lungs and airways. It prevents the release of certain chemicals normally involved in producing immune and allergic responses that result in inflammation.