Abstract: New compounds active in the treatment of ulcers and alergic skin symptoms are prepared by reacting 2-[[5-[(dimethylamino)methyl]furfuryl]thio]ethylmethylsulphide with a suitable compound of formula RH. Said compounds are particularly useful as active principles in pharmaceutical compositions for use in the treatment of affections which require the administration of antagonists for histamine H.sub.2 receptors.