Background: Vajra kandi maathirai (VKM) is a mercury based traditional Siddha drug used to treat various types of fevers and inflammatory diseases. We report our experience of using VKM successfully to treat 5 severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infected patients and its chemical profile. Case report: A family with 5 members age ranges between 13 to 77, both male and females, one with preexisting renal impairment, SARS CoV-2 positive with mild to moderate category were treated with VKM along with the specific dietary practice. The drug was consumed at home quarantine. Real-Time RT PCR from oropharynx swab, X-ray/CT scan chest, hematology, renal function, liver function, body temperature and oxygen saturation were assessed. Blood parameters were repeated after completion of therapy to assess the safety aspect of mercury drug. Chemical profile of the drug was done using Gas chromatography-mass spectrometry and inductively coupled plasma mass spectrometry. Results: With the first dose, the oxygen saturation was improved. Within 3 days of therapy, all symptoms (fever, body pain, cough, and loss of taste) were normalized and renders the Real-Time RT PCR negative for COVID-19. There was no observed side effects and damage to renal and liver. The drug contains 22% of mercury along with a 9-Octadecenoic acid-(E), 1H-Imidazole, 4,5-dihydro-2-(phenylmethyl) and 9,12-Octadecadienoic acid (Z,Z)- as major organic compounds. Conclusion: Vajra kandi maathirai might be a safe drug to manage COVID-19 patients. Rigorous research is required to discover new antiviral molecules from this formulation.