Summary Since relief of cancer pain is an essential part of palliative care medicine, the effectiveness of new analgesic compounds must be validated. For this purpose, we conducted a randomized controlled trial on the analgesic effect of ketamine in palliative care patients. This experiment highlighted numerous obstacles, which we attempt to describe and analyze here. After consulting the investigators, we propose our reflections concerning the adaptation of clinical trials to the specific context of palliative medicine. One notable obstacle is the availability of healthcare teams and their agreement to conduct research with persons they consider vulnerable. Patient availability is also a problem considering the moral and physical capacity of palliative care patients to take part in such studies. In our opinion, short protocols, revised objectives and simplified methodology would be advisable. The development of palliative care units should help enrich the discussion on this ethical issue and facilitate implementation of therapeutic trials.