Aims and objectivesTo determine the effects of nursing interventions for people's nutrition, elimination, mobility and hygiene needs.BackgroundPatient experience of health care is sensitive to nursing quality. A refocus on fundamental nursing care is undermined by lack of evidence of effectiveness for interventions in core areas such as elimination, nutrition, mobility and hygiene.DesignSystematic review.MethodsWe searched for and included experimental studies on interventions by professionally qualified and unregistered nurses that addressed participants' nutrition, elimination, mobility and hygiene needs. We extracted data on scope, quality and results of studies followed by descriptive narrative synthesis of included study outcomes using a novel form of harvest plots.ResultsWe included 149 studies, 35 nutrition, 56 elimination, 16 mobility, 39 hygiene and three addressing two or more areas simultaneously (67 randomised controlled trials, 32 non‐randomised controlled trials and 50 uncontrolled trials). Studies into interventions on participant self‐management of nutrition (n = 25), oral health (n = 26), catheter care (n = 23) and self‐management of elimination (n = 21) were the most prevalent. Most studies focussed their outcomes on observational or physiological measures, with very few collecting patient‐reported outcomes, such as quality of life, experience or self‐reported symptoms. All but 13 studies were of low quality and at significant risk of bias. The majority of studies did not define primary outcomes, included multiple measures of identical concepts, used inappropriate analyses and did not conform to standard reporting quality criteria.ConclusionsThe current evidence for fundamental nursing care interventions is sparse, of poor quality and unfit to provide evidence‐based guidance to practising nurses.Relevance to clinical practiceResearchers in nursing internationally should now undertake a programme of work to produce evidence for clinical practice in the fundamentals of care that is reliable, replicable and robust.