Introduction: Non-tested asymptomatic COVID-19 cases poses threat of transmitting the disease silently. The Siddha polyherbal formulation, Kabasurakudineer, (KSK) was found to be effective in preventing viral replication of SARS-CoV-2 by in-silico studies. A pilot study was conducted to test the antiviral activity of KSK in asymptomatic individuals tested positive for COVID-19. Methods: A single centre, open labelled, randomized controlled study was carried out during June-August 2020, in Tertiary Medical College Hospital, after approval from the institutional ethics committee and registered in CTRI. RTPCR confirmed COVID-19 asymptomatic cases, aged 18-65 years, consented to participate were included and those with co-morbidities like diabetes, hypertension, severe respiratory disease, malignancies, pregnant and lactating mothers were excluded. 60 participants were randomly assigned to study and control group. Study group received KSK (60 ml) along with vitamin C in the morning and zinc in the night, while the control group (CZ) received vitamin C and zinc for 10 days. The primary outcome was the reduction in the SARS-CoV-2 load (ct value), prevention of progression to symptomatic state. Results: In the study group, there was faster reduction in the viral load in terms of ct value as all the 30 participants turned negative for SARS-Co-V2, while 4 remain positive in the control group on the 10th day. The inflammatory markers and serum cytokine findings were inconclusive. No one progressed to the symptomatic state and no adverse event was reported in either groups. Conclusion: This study demonstrated the potential of Kabasurakudineer in reducing the viral load. Further clinical studies are warranted with larger sample size.