Introduction: Exploration of plants as natural repellants to avoid Aedes aegypti mosquitoes that transmit dengue virus to human is worthy. Betel vine leaves (Piper betle L.) could be used as the material of repellant.The study is aimed to test the repellency,potency, and the safety of Piper betel and patchoulli oil modified gel against Aedes aegypti mosquitoes.Methods: This study is an experimental study and used nulliparous (3-5 days old) female Aedes aegypti. Before the study, safety test was done which consists of an irritation test. The effectivity test used five treatments: DEET gel for positive control, piper and patchouli mixture gel, piper only gel, patchouli only gel and gel base only. The five treatments were tested as a repellant with five repetitive applications. The effectiveness of Aedes aegypti's rejection from biting the arms was analyzed using protective percentage. Results: The irritation test showed no safety concerns. Protective percentage analysis shows that modified betel vine gel has estimated mean protective power of over 90% for 6 hours. The data showed that the modified gels has about the same protective percentage as the DEET (ratio: PP (Neem+piper)/PP (DEET) =0.98; 95% confidence interval 0.93, 1.04; p-value=0.50)Conclusion Betel vine oil with modified formulation has a potential to be utilized as Aedes aegypti mosquito repellantand is safe to be used in further repellency tests.