Following a request from the European Commission, the EFSA Panel on Dietetic Products, Nutrition and Allergies (NDA) was asked to deliver a scientific opinion on the safety of Ecklonia cava phlorotannins (marketed as SeaPolynolTM) as a novel food submitted pursuant to Regulation (EC) No 258/97. The novel food is a phlorotannin-rich alcohol extract of Ecklonia cava, which is an edible marine brown alga species. The information provided on the composition, the specifications, the production process and the batch-to-batch variability of the novel food is sufficient and does not raise safety concerns. The intention is to market the novel food as a food supplement for healthy individuals over the age of 12 years. A subchronic repeated dose oral toxicity study in rodents tested the novel food at daily doses of 0, 375, 750 and 1,500 mg/kg body weight (bw). The Panel considers the middose as the no-observed-adverse-effect-level (NOAEL) of the study. Taking into account this NOAEL of 750 mg/kg bw per day and by applying an uncertainty factor of 200, the Panel considers an intake level of 3.75 mg/kg bw per day as safe. The Panel concludes that the novel food, Ecklonia cava phlorotannins, is safe for the use in food supplements at a maximum daily intake level of 163 mg/day for adolescents from 12 to 14 years of age, 230 mg/day for adolescents above 14 years of age and 263 mg/day for adults.