Due to rapid international market development, there is a strong and urgent need to assess the safety of the novel food, Ilex guayusa. Guayusa has been consumed for centuries in the western Amazon as an herbal tea, and novel food regulation provide a detailed framework for safety assessment of novel foods with such a history of use. This study reviews guayusa’s taxonomy, chemical composition, toxicology, ethnobotany, and history of safe use as key elements of a robust novel food safety assessment. Guayusa is a product of traditional agricultural systems with a continuous history of consumption in Ecuador. Its known chemical composition appears to present no greater risk to human health than existing teas such as green tea or yerba mate, although our understanding of guayusa’s chemical profile is still nascent, requiring further investigation. Broad consumption of guayusa is not associated with a history of adverse effects or product safety notifications. Biochemical and phytochemical studies have profiled its nutritional content, metabolite composition, and bioactivity, validating guayusa’s antioxidant and stimulant properties. In conclusion, guayusa leaves have a well-documented chemical composition and history of safe use, which are key considerations for authorization as a novel food in the EU.