Abstract: 8-Aryl-1,2,3,4-tetrahydroisoquinoline and derivatives thereof having the formula ##STR1## and the non-toxic pharmacologically acceptable acid addition salts thereof; wherein R is hydrogen, benzyl, or an alkyl radical of 1 to 7 carbon atoms; R.sup.1 is hydrogen or an alkyl radical of 1 to 7 carbon atoms; R.sup.2 in each occurrence is hydrogen, an alkyl radical of 1 to 7 carbon atoms or alkoxy radical of 1 to 7 carbon atoms, alike or different; Ar is phenyl optionally substituted with one or more halogen, an alkyl radical of 1 to 7 carbon atoms, or alkoxy radical of 1 to 7 carbon atoms; and n is positive integer less than 4, are disclosed. These compounds are useful because of their anti-arrhythmic, antimicrobial and central nervous system activity.