Abstract: The invention provides a method for the treatment of a human or animal patient suffering from, or subject to, an arthritic or related autoimmune disorder, a connective tissue disorder or transplant rejection, using a compound which is a tetrazole derivative of the formula: ##STR1## wherein R.sup.1 represents halogen, alkyl, alkoxy, alkylthio, alkylsulphinyl, alkylsulphonyl, alkylsulphamoyl, dialkylsulphamoyl, dialkylamino, dialkylcarbamoyl, alkanoyl, alkoxycarbonyl, alkoxycarbonylamino, alkylcarbamoyl, alkanoylamino, cycloalkylcarbonyl, hydroxy, formyl, nitro, trifluoromethyl, trifluoroacetyl, aryl, benzyloxycarbonylamino, amino, sulphamoyl, cyano, tetrazol-5-yl, carboxy, carbamoyl, benzyloxy, aralkanoyl, aroyl, or a group of the formula --CR.sup.2 .dbd.NOR.sup.3 wherein R.sup.2 represents hydrogen, alkyl, aryl, aralkyl, trifluoromethyl or cycloalkyl, and R.sup.