###Human: Is it possible to get cold sores due to STD? ###Assistant: Hi. Most of the cold sores are due to HSV-1. If it is associated with genital lesions then more chances of STDs are there. If only cold sores, it is due to less immunity. Giving oral may or may not be the cause. As prevention, you both check for STDs but they are unlikely to be positive in your case. If one has cold sores, the partner gets it easily. Apply Zovirax (Acyclovir) ointment.