Aims and objectives. To identify the mechanisms of subcutaneous fluid administration in advanced illness. Background. Hydration at end of life is a fundamental issue in quality care internationally. Decision-making regarding the provision of artificial hydration in advanced illness is complicated by a paucity of evidence-based guidance. Despite considerable attention given to the topic including two recent Cochrane reviews, there has been no focus in systematically identifying papers that report the mechanisms for delivering hydration subcutaneously. Consequently, there is a need to produce guidance on the site, mode, volume and rate of infusion, based on empirical evidence. Design. Systematic review of papers reporting empirical research data. Methods. Key databases (CENTRAL, Medline, EMBASE, Web of Science, CINAHL) were searched in September 2015, with no date limitations. Inclusion criteria focused on hypodermoclysis in adults within an advanced illness population. Selected studies were reviewed for quality and a risk-of-bias assessment was conducted for the included studies. Results. Fourteen papers were included in the analysis; most (n = 8) were conducted in hospices with others (n = 6) in long-stay units with a population affected by chronic conditions associated with ageing. Studies were of moderate or high quality. The site and mode of infusion were not well described in these papers, and rates of infusion varied widely allowing for little clear consensus to guide clinical practice in the administration of subcutaneous fluids. Conclusions. Studies under-report the mechanisms by which artificial hydration is provided, creating a paucity of evidence-based guidance by which to practice. There is a need for evidence generated from nonmalignant populations to ensure applicability to the large number of people with other advanced illness. Relevance to clinical practice. In the absence of sufficiently powered robust evidence, the mode of delivery of artificial hydration at end of life remains in the gloaming between evidence and unfounded habit.