A novel and inexpensive way for chronic kidney disease (CKD) patients to relieve their upper gastrointestinal symptoms without medication is to rinse with mouthwashes that dilute saliva and/or displace bitter-tasting compounds, such as urea, a new study finds.

Karen J. Manley, MSc, a renal dietitian from Austin Health in Victoria, Australia, tested 4 mouthwashes in random order on 42 pre-dialysis patients with stage 4-5 CKD (average age 69; glomerular filtration rate less than 30 mL/min/1.73m2) from an outpatient renal clinic in 2014. The rinses included sodium bicarbonate (5g), salt (5g), citric acid (1g), and de-ionized water, each in a 500 mL solution.

Based on the Patient Generated-Subjective Global Assessment, the participants had complained of more than 1 of the following symptoms: poor appetite, nausea, lack of taste, vomiting, and dry mouth. All patients reported poor appetite, most noted taste changes, and half complained of nausea and dry retching.

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Saliva testing confirmed increased concentrations of urea, potassium, and bicarbonate and higher pH levels. Investigators also assessed patients for individual genetic sensitivities to bitter and other tastes (e.g., salty, sour, sweet) and classified patients as non-tasters, tasters, or hyper-tasters. Mouth bacteria were not measured, however.

“Water mouth rinses generally improved all symptoms including dry mouth, taste changes, nausea, and dry retching, while sodium bicarbonate was found to be more effective in improving taste changes, nausea, and dry retching,” Manley told Renal & Urology News. “The salt solution was beneficial in improving nausea and dry retching. Citric acid improved dry mouth and taste changes, but some patients found it increased nausea and dry retching.”

Most patients (66%) found sodium bicarbonate beneficial, with 40% preferring it to the other mouth rinses, according to results published online ahead of print in Nephrology. Manley explained that sodium bicarbonate cleanses receptors on taste buds and may favorably alter mouth pH. The mouth rinses also may be beneficial for chemotherapy and pregnancy patients.


  1. Manley K. Will mouth wash solutions of water, salt, sodium bicarbonate or citric acid improve upper gastrointestinal symptoms in chronic kidney disease? Nephrology. doi:10.1111/neph.12753.