Abstract Following a request from the European Commission, the EFSA Panel on Nutrition, Novel Foods and Food Allergens (NDA) was asked to deliver an opinion on water extract of Cistanche tubulosa stems as a novel food (NF) for its use in food supplements (FS) and foods for special medical purposes (FSMP). The target population is the general adult population excluding pregnant and lactating women. The applicant proposes a maximum daily intake of 2 g for FS and a maximum use level of 10% in FSMP. The characteristic components of the extract are phenylethanoid glycosides (at least 70% of the NF), in particular, echinacoside (25–45% of the NF). The NF has been authorised as a prescription drug in China in 2005 for the treatment of vascular dementia. The Panel notes that an integrated analysis of three studies covering 1,076 patients with vascular dementia treated with the proposed NF at a daily dose of 1,800 mg, reported that 12 adverse events (AEs) were classified to be ‘definitely’, ‘probably’ or ‘possibly related’ to the exposure to the NF. Two of these AE were classified as severe (cerebral haemorrhage and epilepsy). The Panel considers that the reported AEs raise safety concerns. The Panel also notes the limitations of the provided toxicological studies, in particular the non‐compliance with the EFSA approach on the genotoxicity testing strategy and the non‐compliance with good laboratory practice (GLP) and the respective OECD Guidance documents of the repeated dose toxicity studies. In view of the AEs in the human studies, the Panel considers that additional toxicological studies, following testing guidelines would not be able to overcome the concerns raised from the human studies. The Panel concludes that the safety of the NF has not been established.