Abstract: Antimicrobial compounds are disclosed having the formula:Z--B--Y--B--Z .nHAwherein B is carbamylguanidino, or thiocarbamylguanidino, Y is a bivalent organic radical selected from the group consisting of C.sub.2 -C.sub.12 alkylene, C.sub.5 -C.sub.12 cycloalkylene, C.sub.5 -C.sub.12 cycloalkylenebis(loweralkyl), C.sub.6 -C.sub.12 arylene and loweralkylarylene, C.sub.7 -C.sub.12 aryleneloweralkyl, and C.sub.8 -C.sub.12 arylenebis(loweralkyl) and Z is selected from the group consistng of C.sub.1 -C.sub.2 alkyl; C.sub.4 -C.sub.12 dialkylaminoalkyl; C.sub.3 -C.sub.12 alkenyl; C.sub.3 -C.sub.12 alkynyl; C.sub.3 -C.sub.12 cycloalkyl, C.sub.4 -C.sub.12 cycloalkylalkyl; C.sub.1 -C.sub.10 alkoxy C.sub.10 -C.sub.2 alkyl having a total carbon content of C.sub.3 -C.sub.14 ; C.sub.1 -C.sub.10 alkythio C.sub.10 -C.sub.2 alkyl having a total carbon content of C.sub.3 -C.sub.14 ; phenoxy C.sub.2 -C.sub.6 alkyl; phenylthio C.sub.2 -C.sub.6 alkyl; C.sub.6 -C.sub.14 aryl; C.sub.7 -C.sub.14 aralkyl and arylcycloalkyl; and C.sub.