Oral formulation containing an anti-ulcer drug comprises: (a) an inert nucleus； (b) a coating which is soluble or disintegrates rapidly in water obtained from a single aqueous or aqueous-alcoholic solution/suspension comprising an active agent of formula (I), (II), or (III), and at least one excipient chosen from a ligand, an alkaline compound, a surfactant, a filler, and a disaggregant-swelling agent； and (c) an outer gastro-resistant coating comprising an enteric coating polymer and at least one excipient chosen from a plasticiser, a surfactant, a pigment and a lubricant. A = a group of formula (i) or (ii)； R3, R5 = H, alkyl, alkoxy, or alkoxyalkoxy； R4 = H, alkyl, alkoxy (optionally fluorinated), alkoxyalkoxy, or alkoxycycloalkyl； R1 = H, alkyl, halo, cyano, carboxy, carboalkoxy, carboalkoxyalkyl, carbamyl, carbamylalkyl, hydroxy, alkoxy, hydroxyalkyl, trifluoromethyl, acyl, carbamyloxy, nitro, acyloxy, aryl, aryloxy, alkylthio, or alkylsulphinyl； R2 = H, alkyl, acyl, carboalkoxy, carbamyl, alkylcarbamyl, dialkylcarbamyl, alkylcarbonylmethyl, alkoxycarbonylmethyl or alkylsulphonyl； and m = 0-4.
