trans-Khellactone is a coumarin derivative used in pharmaceutical research for its anti-inflammatory, antiviral, and antioxidant properties. It shows potential in inhibiting enzymes involved in viral replication, making it a candidate for antiviral drug development. Additionally, it exhibits vasodilatory effects, smooth muscle relaxation, and blood pressure-lowering activity, supporting applications in cardiovascular therapies for conditions like hypertension and angina. Studies also indicate potential anticancer activity by inhibiting the growth of certain cancer cells, including liver and breast cancer. Naturally occurring in traditional medicinal plants such as Ammi visnaga, it contributes to the biological activity of herbal extracts used for treating respiratory and circulatory disorders.