Abstract: Novel compounds, compositions and methods effective for the prevention and treatment of mast-cell mediated inflammatory disorders are described. The compounds, compositions and methods are effective for the prevention and treatment of inflammatory diseases associated with the respiratory tract, such as asthma and allergic rhinitis, as well as other types of immunomediated inflammatory disorders, such as rheumatoid arthritis, conjunctivitis and inflammatory bowel disease, various dermatological conditions, as well as certain viral conditions. The compounds comprise potent and selective inhibitors of the mast cell protease tryptase. The compositions for treating these conditions include oral, inhalant, topical and parenteral preparations as well as devices comprising such preparations.