Herpes Simplex Virus types 1 and 2 (HHV-1 and HHV-2) are human neurotropic viruses that infect most commonly the oral and genital area, respectively. Resistant viral isolates can be observed especially in immunocompromised patients. This scenario has triggered the search for new antiherpetic agents, especially those with mechanisms of action different to nucleoside analogs. The antiviral activity in vitro for abietic and dehydroabietic acid and controls [acyclovir (ACV), and heparin (HEP)] was evaluated against HHV-1 and HHV-2 using end-point titration technique (EPTT) with a few modifications. The compounds methyl abietate [2], abietinal [4], 8,13(15)-abietadien-18-oic acid [5], methyl abieta-8,13(15)-dien-18-oate [6], 8,13(15)-abietadien-18ol [7] and dehydroabietinol acetate [11] showed significant anti-herpetic activity of broad-spectrum.