Abstract: This invention relates to an improved anti-ulcer composition for prophylaxis and treatment of stomach and duodenum ulcers, including stress ulcers. The composition provides potent anti-ulcer activity with a dramatic reduction in toxicity and harmful side effects. The composition comprises a histamine H.sub.2 antagonist based on a guanidine derivative, preferably [N-cyano-H'-methyl-N"]-2(4-methyl-imidazolyl)-methylthio-[ethylguanidine]; and at least one 4-phenyl-tetrahydroisoquinoline antidepressant, preferably the [+] isomer of 4-phenyl-2-methyl-8-amino-1,2,3,4-tetrahydroisoquinoline hydrogen maleate. The composition may also contain a spasmolytic agent, preferably 2-metoxycarbonyl-4-(beta-piperidino ethyl) -metoxycarbonyl-4-(beta-peperidinoethyl) benzophenone. The ratio of antagonist to antidepressant ranges from 2:1 to 60:1, and the ratio of their sum to the spasmolytic agent, when used, ranges from 2.2:1 to 42.5:1.

Abstract: The invention relates to tetrahydroisoquinoline derivatives of the Formula ##STR1## wherein R.sub.1, R.sub.2, R.sub.3 and R.sub.4 are each selected from the group consisting of a hydrogen and a hydroxyl group. These derivatives are useful in tocology (obstetrics).Administration of the inventive compounds induces relaxation of uterine muscles, a property that is particularly useful in cases of second trimester miscarriage, premature birth up to the 37th or 38th week of pregnancy, and during delivery. The compounds are especially useful from the onset of labor up to delivery of the newborn's head, a period which is often accompanied or complicated by frequent, violent, uncoordinated contractions of the uterus. The compounds are also useful in obstetric and gynecological operations, such as a hysterectomy, surgery for acute placental insufficiency, etc.