Cyclic sulphur compounds

Certain tricyclic sulphone compounds each of which is substituted in the 1-,2-,3- or 4-position by a carboxyl or (5-tetrazolyl) group and each of which is optionally substituted in the 5-,6-,7- or 8-position by a second carboxyl or (5-tetrazolyl) group or a substituent selected from cyano, halogen, nitro, alkyl, alkoxy, acyl, amino, acylamino, thioalkyl, alkylsulphinyl and alkylsulphonyl, as well as salts, and optionally substituted esters and amides of the carboxyl substituted compounds and alkyl derivatives of the tetrazolyl substituted compounds, are useful for the relief or prophylaxis of allergic conditions.