Introduction: Cyanthillium cinereum is a native of tropical Africa and Asia (India, Indochina, Indonesia) and is used as a smoking cessation drug and relief for cold. Leaves act as an abortifacient and blood purifier and have diuretic, antiviral, analgesic, antipyretic, and anti-inflammatory properties. Cinnamon is the inner bark of cinnamon cassia found on the west coast of India, Sri Lanka, and Indonesia. It is a forest evergreen tree that has antioxidant, anti-inflammatory, anti-diabetic, and anti-microbial properties, treats bronchitis, diabetes and has traces of Vitamin B & K. Hence, we aimed to study the antioxidant activity and cytotoxicity in the herbal synergy of cinnamon and cyanthillium cinereum. Materials and Methods: An in vitro study was conducted, and the polar aqueous extract of this combination of herbs cinnamon \ and cyanthilium cinereum was prepared and tested for DPPH assay assay to study its antioxidant properties and the absorbance value was evaluated. Brine Shrimp Assay with viable nauplii cell lines was used for cytotoxicity assessment. Results: Antioxidant activity of the aqueous extract of Cyanthillium cinereum and Cinnamon revealed that there was a decrease in the antioxidant activity with an increase in the concentration of the aqueous extract. Cytotoxicity of the aqueous extract of Cyanthillium cinereum and Cinnamon reported an increase in the cytotoxic activity with a rise in the concentration of the aqueous extract. Conclusion: This research showed that aqueous extract of cinnamon and cyanthillium cinereum has good antioxidant activity, is less cytotoxic, and can be used as a therapeutic and preventive medicine.