In chronic rhinopharyngotubaric phlogoses, the key pathogenic element sustaining phlogosis is a persistent modification of the biological, rheological features of the nasal mucus. For centuries sulphurous thermal waters have proved effective in clinically curing such phlogoses. In order to evaluate the effect of such sulphurous-salty-bromic-iodic thermal waters a randomized, double blind study was undertaken on a sampling of 50 patients. The effect such waters have on secretory IgA (sIgA) and albumin in the nasal secretions was tested against a placebo made of distilled water. Using the method of radial immunodiffusion, the response in the IgAs (mg/l) and albumin (mg/dl) concentrations in the nasal secretions was measured for 25 patients treated with the thermal waters and 25 patients treated with distilled water. The average concentrations were statistically compared using the Student t-test for paired samples. A significant increase (p < 0.0001) was seen in the mean IgAs concentration in the patients treated with the thermal waters. On the other hand, there was a weak, not statistically significant increase in the same data mean for the group treated with distilled water. The average increase in the albumin concentration in the nasal secretions proved significant in both cases although the significance was much more marked in the group treated with the thermal waters (p = 0.001) vs. the placebo group (p = 0.039).