Postnasal drip (PND)-related cough is a very common symptom in patients with upper respiratory tract infections (URTIs). At present, there is not a standard treatment for postnasal drip and postnasal drip-related cough. The aim of this pilot study was to evaluate the efficacy of a specific salso-bromo-iodine thermal water containing hyaluronic acid and grapefruit seed extract (SBI-H-GSE) comparing it with a normal saline solution in children with URTIs who refer PND-related symptoms. The study was randomized, single-blind, and controlled. Study group (75 children) was treated with SBI-H-GSE and control group (65 children) was treated with a normal saline solution; both compounds were administered by nasal nebulization with Rinowash nasal douche twice/day for 10 days a month for 3 consecutive months. Parent Cough-Specific Quality of Life questionnaire (PC-QOL) average score, the prevalence of symptoms and signs related to post-nasal drip, nasal mucociliary transport time (NMTT), duration and number of URTI episodes, antibiotic usage and days of absence from school were evaluated at baseline and after treatment. SBI-H-GSE therapy shows better and statistically significant trend after treatment when compared to control group for PC-QOL average score (p=0.011), NMTT (p=0.047), symptoms and signs related to post-nasal drip (all p<0.005, except for the cobblestone appearance of the mucosa), duration (in days) with URTI symptoms (p=0.023) and a usage of antibiotic therapy (p=0.011). The current randomized-controlled pilot study demonstrated that SBI-H-GSE solution was effective in the treatment of children with URTIs who refer PND-related symptoms.