Nedocromil is a medication considered as mast cell stabilizer used to treat itching associated with allergic conjunctivitis. Nedocromil has been shown to inhibit the in vitro activation of, and mediator release from, a variety of inflammatory cell types associated with asthma, including eosinophils, neutrophils, macrophages, mast cells, monocytes, and platelets. Nedocromil inhibits activation and release of inflammatory mediators such as histamine, prostaglandin D2 and leukotrienes c4 from different types of cells in the lumen and mucosa of the bronchial tree. These mediators are derived from arachidonic acid metabolism through the lipoxygenase and cyclo-oxygenase pathways. The mechanism of action of nedocromil may be due partly to inhibition of axon reflexes and release of sensory neuropeptides, such as substance P, neurokinin A, and calcitonin-geneñrelated peptides. The result is inhibition of bradykinin-induced bronchoconstriction. Nedocromil does not possess any bronchodilator, antihistamine, or corticosteroid activity. Nedocromil is indicated for the treatment of itching associated with allergic conjunctivitis.