This invention provides novel salt and crystalline forms thereof of (-)4-(4-fluorophenyl)-7-[({5-[1-hydroxy-1-(trifluoromethyl)propyl]-1,3,4-- oxadiazol-2-yl}amino)-methyl]-2H-chromen-2-one. The compounds are 5-LO inhibitors and are useful for treatment of conditions such as asthma, allergic rhinitis, COPD, and atherosclerosis.