Nedocromil (Na) is anti-inflammatory agent used in the maintenance treatment of mild to moderate asthma. Therapeutic trials have shown that nedocromil is effective in the therapy of adult patients whose asthma is not controlled by beta-agonists alone. It has actions are similar to those of cromolyn and its safety and efficacy in the treatment of mild to moderate asthma is equivalent to cromolyn sodium. Nedocromil was approved for management of asthma in adults in December 1992. It was subsequently approved for use in children 2 years and older on 17 sep 97. Topical nedocromil is being investigated for use in allergic conjunctivitis. The exact mechanism by which nedocromil exerts its antiinflammatory effects is unknown. Although nedocromil is similar in some ways to cromolyn, distinct differences exist. It appears that both cromolyn and nedocromil are similar in their ability to antagonize antigen-induced mast cell degranulation, but nedocromil prevents bronchoconstriction secondary to non-antigenic stimuli at much lower doses than does cromolyn By interfering with mast cell degranulation, nedocromil inhibits the release of histamine.