The synthesis of a new acyclic analogue of deoxyguanosine, 9-[(1,3-dihydroxy-2-propoxy)methyl]guanine (DHPG, 1), is described starting from epichlorohydrin via condensation of 2-O-(acetoxymethyl)-1,3-di-O-benzylglycerol (5) with N2,9-diacetylguanine (6). In vitro studies indicate that DHPG is a potent and broad-acting (herpes simplex virus types 1 and 2, cytomegalovirus, and Epstein-Barr virus) antiherpetic agent. In vivo studies indicate its lack of toxicity [LD50 (mice) = 1-2 g/kg, ip] and its superiority over acyclovir [oral ED50 = 7 (mg/kg)/day vs. 550 (mg/kg)/day in HSV-2 infected mice].