Natural Treatments for Oral Disorders in Palliative Care: A Systematic Review

Palliative care (PC) aims to enhance quality of life and alleviate suffering in patients with advanced or degenerative diseases. Oral disorders (ODs) are common among PC patients, often impairing essential functions such as chewing, swallowing, and communication. The use of natural treatments for these conditions appears promising. This systematic review aimed to evaluate the efficacy, acceptability, and potential adverse events (AEs) and oral tolerability profiles of natural products used for managing ODs in patients undergoing PC. We conducted the review in accordance with Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines and registered it in International Prospective Register of Systematic Reviews (protocol number: CRD42024591279). A comprehensive literature search was performed on multiple biomedical databases (PubMed, Cumulative Index to Nursing and Allied Health Literature, Web of Science, Scopus, and Cochrane Library), applying rigorous inclusion criteria. Included studies were assessed for quality using the Joanna Briggs Institute (JBI) Critical Appraisal Tools and the Oxford Centre for Evidence-Based Medicine levels of evidence. Out of 1075 identified records, 7 studies met the inclusion criteria, mostly randomized controlled trials (n = 5) with 522 PC patients. The studies had moderate to high methodological quality (mean = 88.4%, range = 64%-100%). Glycerol, Salvia officinalis, and peppermint mini ice cubes relieved oral symptoms. Glycerol gave rapid, short-lived relief; salvia improved dryness versus saline; peppermint cubes reduced dry mouth and thirst and were preferred. Cannabinoid trials did not prospectively assess ODs but were retained only as contextual evidence on oral AEs/tolerability and the feasibility of the oro-buccal route. Natural interventions may relieve xerostomia and improve comfort, but generalizability remains limited; future randomized trials with oral-specific endpoints, transparent dosing, and longer follow-up are required.