Marine organisms offer an infinite supply of resources for discovering useful therapeutic agents. Apart from foods derived from the marine environment, a wide variety of bioactive substances are being isolated and characterized several with great promise for the treatment of human diseases. Currently, most infectious diseases can be controlled with natural or synthetic drugs. We are still in need of safer, cheaper, and more effective drug products. This study characterized bioactive substances in Eudistoma viridae by GC-MS analysis. The GC-MS analysis of the methanol extract confirmed the presence of 12 active compounds. Several compounds were confirmed in the Ascidian extract, including a prominent steroid peak (26.90%). These compounds may be responsible for different pharmacological actions.