Derivatives useful disulfide for the treatment of allergic diseases

"Disulfide DERIVATIVES USEFUL FOR THE TREATMENT OF ALLERGIC". The present invention relates to diphenyl disulfide derivatives of formula (I) wherein X is -NHC (= O) NH-R and R is as defined in the claims are useful for treating or preventing allergic diseases of the eye, nose, , skin, ear, gastrointestinal tract, airways or lung and preventing or treating manifestations of systemic mastocistose. The disulfide derivatives act as mast cell stabilizers.