Black seed oil is an herbal ingredient derived from the plant Nigella sativa, which is native to Eastern Europe and Western Asia. Black seed oil, which is extracted from the seeds, is often touted as a way to treat certain health conditions. Black seed oil contains antioxidants and bioactive compounds. Black seed oil contains a compound called thymoquinone. In an animal study, thymoquinone was shown to have antioxidant properties, while a human study showed anti-inflammatory effects. But a 2014 review of existing studies noted that more research is needed to explore thymoquinone’s effectiveness as a medical treatment.