Reviewed: Morales-Bozo I, Ortega-Pinto A, Rojas Alcayaga G, et al. Evaluation of the effectiveness of a chamomile (Matricaria chamomilla) and linseed (Linum usitatissimum) saliva substitute in the relief of xerostomia in elders [published online January 14, 2016]. Gerodontology. March 2017;34(1):42-48.

Xerostomia, a condition commonly known as dry mouth, can be caused by a variety of factors, including systemic conditions (e.g., diabetes mellitus and rheumatoid arthritis), mouth breathing, local radiotherapy, and use of tobacco (Nicotiana tabacum, Solanaceae) or certain prescription pharmaceuticals. Aging also causes dry mouth due to decreased saliva production and reduced mucin expression from epithelial cells. In the elderly, dry mouth is a permanent, progressive condition that adversely affects quality of life. Saliva substitutes are often recommended and work by temporarily lubricating the mouth.

Chamomile (Matricaria recutita syn. M. chamomilla, Asteraceae) flower extract has been shown to help reduce oral discomfort and mucositis (mucous membrane inflammation) in patients, and flax (Linum usitatissimum, Linaceae) seed produces a water-soluble mucilage that can hydrate the mucosa. The purpose of this randomized, double-blind, crossover study was to evaluate a saliva substitute made of chamomile flower and flax seed for older patients with dry mouth.

Patients over the age of 60 who had dry mouth were recruited in Santiago, Chile, from the University of Chile School of Dentistry and the Health Reference Centre of Peñalolén Cordillera Oriente. Patients with oral mucosa lesions, oral motor disorders, or cognitive limitations were excluded from the study.

For one week, patients (N = 74; mean age = 66.7 ± 6.47 years) were treated with either 2 mL of a commercial carboxymethyl cellulose-based saliva substitute (Farmacias Ahumada; Santiago, Chile) or 2 mL of an herbal preparation made by the study authors (an infusion of 30 g of flax seed and 1 g of chamomile flowers in one liter of water) four times per day. After a one-week washout period, the patients switched to the other treatment. Before and after each treatment phase, the severity of dry mouth symptoms was measured by a 10-point visual analog scale (1 = absence of symptom, 10 = “maximum imagined symptomatic perception”). The primary endpoint was the change in symptoms of dry mouth from baseline to treatment end.

Nearly all (92%) of the patients were women. At baseline, 45% of the patients had a salivary flow of 0.2 mL or less per minute (hyposialia), and 55% had normal flow (between 0.2 and 1.0 mL per minute). The authors reported the following dry mouth-related factors in the study participants: disease (arterial hypertension, “depressive symptoms,” and arthritis were the three most common conditions), medication use, smoking, and maxillofacial radiation. At baseline, 59.5% of the patients had a sensation of thick saliva, 27% had a sensation of “burning tongue,” 54.1% needed to drink liquids to swallow, and 56.8% had difficulty swallowing food.

Compared to baseline, the herbal saliva substitute significantly improved dry mouth (P = 0.003), sensation of thick saliva (P = 0.028), sensation of burning tongue (P = 0.038), and difficulty in swallowing food (P = 0.001). The conventional saliva substitute significantly improved only two symptoms: dry mouth sensation (P = 0.002) and needing to drink liquids to swallow (P = 0.019), compared to baseline. The herbal saliva substitute was significantly more effective than the conventional saliva substitute at decreasing symptom severity of dry mouth (P = 0.022), sensation of thick saliva (P = 0.048), and difficulty in swallowing food (P = 0.001).

The authors conclude that the herbal saliva substitute improved more symptoms than the conventional treatment. Limitations of the study include the short treatment duration (especially given the chronic nature of dry mouth in elderly individuals), the unequal gender ratio of participants, and the lack of reported adverse side effects (if any). The safety of long-term use of this herbal treatment should also be evaluated. “The Chilean elderly population has a natural relation with these herbaceous plants by frequently using them as food additives or as teas,” the authors note. Therefore, they suggest that the chamomile-flax herbal preparation, which is inexpensive and can be made at home, may be an appealing option in Chile, where treatments for dry mouth are limited.

—Heather S. Oliff, PhD