BACKGROUND: People with central neurological disease or injury have a much higher risk of both faecal incontinence (FI) and constipation than the general population. There is often a fine line between the two symptoms, with management intended to ameliorate one risking precipitating the other. Bowel problems are observed to be the cause of much anxiety and may reduce quality of life in these people. Current bowel management is largely empirical, with a limited research base. The review is relevant to individuals with any disease directly and chronically affecting the central nervous system (post-traumatic, degenerative, ischaemic or neoplastic), such as multiple sclerosis, spinal cord injury, cerebrovascular disease, Parkinson's disease and Alzheimer's disease. This is an update of a Cochrane Review first published in 2001 and subsequently updated in 2003, 2006 and 2014. OBJECTIVES: To assess the effects of conservative, physical and surgical interventions for managing FI and constipation in people with a neurological disease or injury affecting the central nervous system. SEARCH METHODS: We searched the Cochrane Incontinence Specialised Register (searched 27 March 2023), which includes searches of the Cochrane Central Register of Controlled Trials (CENTRAL), MEDLINE, MEDLINE In-Process, MEDLINE Epub Ahead of Print, ClinicalTrials.gov, WHO ICTRP as well as handsearching of journals and conference proceedings; and all reference lists of relevant articles. SELECTION CRITERIA: We included randomised, quasi-randomised (where allocation is not strictly random), cross-over and cluster-randomised trials evaluating any type of conservative, physical or surgical intervention against placebo, usual care or no intervention for the management of FI and constipation in people with central neurological disease or injury. DATA COLLECTION AND ANALYSIS: At least two review authors independently assessed the risk of bias in eligible trials using Cochrane's 'Risk of bias' tool and independently extracted data from the included trials using a range of prespecified outcome measures. We produced summary of findings tables for our main outcome measures and assessed the certainty of the evidence using GRADE. MAIN RESULTS: We included 25 studies with 1598 participants. The studies were generally at high risk of bias due to lack of blinding of participants and personnel to the intervention. Half of the included studies were also at high risk of bias in terms of selective reporting. Outcomes were often reported heterogeneously across studies, making it difficult to pool data. We did not find enough evidence to be able to analyse the effects of interventions on individual central neurological diseases. Additionally, very few studies reported on the primary outcomes of self-reported improvement in FI or constipation, or Neurogenic Bowel Dysfunction Score. Conservative interventions compared with usual care, no active treatment or placebo Thirteen studies assessed this comparison. The interventions included assessment-based nursing, holistic nursing, probiotics, psyllium, faecal microbiota transplantation, and a stepwise protocol of increasingly invasive evacuation methods. Conservative interventions may result in a large improvement in faecal incontinence (standardised mean difference (SMD) -1.85, 95% confidence interval (CI) -3.47 to -0.23; 3 studies; n = 410; low-certainty evidence). We interpreted SMD ≥ 0.80 as a large effect. It was not possible to pool all data from studies that assessed improvement in constipation, but the evidence suggested that conservative interventions may improve constipation symptoms (data not pooled; 8 studies; n = 612; low-certainty evidence). Conservative interventions may lead to a reduction in mean time taken on bowel care (data not pooled; 5 studies; n = 526; low-certainty evidence). The evidence is uncertain about the effects of conservative interventions on condition-specific quality of life and adverse events. Neurogenic Bowel Dysfunction Score was not reported. Physical therapy compared with usual care, no active treatment or placebo Twelve studies assessed this comparison. The interventions included massage therapy, standing, osteopathic manipulative treatment, electrical stimulation, transanal irrigation, and conventional physical therapy with visceral mobilisation. Physical therapies may make little to no difference to self-reported faecal continence assessed using the St Mark's Faecal Incontinence Score, where the minimally important difference is five, or the Cleveland Constipation Score (MD -2.60, 95% CI -4.91 to -0.29; 3 studies; n = 155; low-certainty evidence). Physical therapies may result in a moderate improvement in constipation symptoms (SMD -0.62, 95% CI -1.10 to -0.14; 9 studies; n = 431; low-certainty evidence). We interpreted SMD ≥ 0.5 as a moderate effect. However, physical therapies may make little to no difference in Neurogenic Bowel Dysfunction Score as the minimally important difference for this tool is 3 (MD -1.94, 95% CI -3.36 to -0.51; 7 studies; n = 358; low-certainty evidence). We are very uncertain about the effects of physical therapies on the time spent on bowel care, condition-specific quality of life and adverse effects (all very low-certainty evidence). Surgical interventions compared with usual care, no active treatment or placebo No studies were found for surgical interventions that met the inclusion criteria for this review. AUTHORS' CONCLUSIONS: There remains little research on this common and, for patients, very significant issue of bowel management. The available evidence is almost uniformly of low methodological quality. The clinical significance of some of the research findings presented here is difficult to interpret, not least because each intervention has only been addressed in individual trials, against control rather than compared against each other, and the interventions are very different from each other. Understanding whether there is a clinically-meaningful difference from the results of available trials is largely hampered by the lack of uniform outcome measures. This is due to an absence of core outcome sets, and development of these needs to be a research priority to allow studies to be compared directly. Some studies used validated constipation, incontinence or condition-specific measures; however, others used unvalidated analogue scales to report effectiveness. Some studies did not use any patient-reported outcomes and focused on physiological outcome measures, which is of relatively limited significance in terms of clinical implementation. There was evidence in favour of some conservative interventions, but these findings need to be confirmed by larger, well-designed controlled trials, which should include evaluation of the acceptability of the intervention to patients and the effect on their quality of life.