BACKGROUND: Microcirculation disturbance of pharynx may be one of the pathogenesis base caused recurrent attacks of chronic pharyngitis. The negative pressure can improve the microcirculation of inflammary target organs by biomechanical changes.OBJECTIVE: To explore the therapeutic effect of oral negative pressure on patients with chronic pharyngitis and nail fold microcirculation.DESIGN: A randomized single blind controlled observation.SETTING: Department of Pathophysiology of Hebei North University.PARTICIPANTS: A total of 65 patients with chronic pharyngitis and course of disease about 1-3 years admitted to Department of Neurology,First affiliated Hospital of Hebei North University from January to September 2002 were selected. They were randomly divided into treatment group (n=35) and control group (n=30), including 36 cases with chronic pharyngitis (18 cases from the treatment group, 18 cases from the control group), 29with chronic hypertrophied pharyngitis (17 cases from the treatment group,12 cases from the control group).METHODS: The Hices oral negative pressure instrument was used and the negative pressure exert equipment was put into the optimal position of the patients' mouth to keep the negative pressure of (0.05±0.01) Mpa, 10minutes once (the first therapy time was 5 minutes), once daily and the time was fixed, 5 days as a period of therapy for three periods. Patients in the control group were also given the negative pressure exerts equipment,but no negative pressure was exerted.MAIN OUTCOME MEASURES: ① Observation and evaluation of nail fold microcirculation: The nail fold microcirculation was observed by the XTL- Ⅱ microcirculation micro-television system, and the first row nail fold of the left ring figure was checked conventionally to record the state of microvessel, state of micro-bloodstream and peri-loop. The degree of microcirculatory disturbance was quantitatively analyzed according to Tian Niu's weighing integral method, the lower the scores, the better the microcirculation. ②The improvement of chronic pharyngitis after treatment of 3courses.RESULTS: Totally 65 patients with chronic pharyngitis entered the stage of result analysis. ①After 1 course of treatment, the symptoms of 1/3 of the patients in the treatment group were significantly improved; after 3 courses of treatment, except there was no obvious changes of hypertrophied morphology such as lymphatic follicle proliferation on posterior wall of throat and hypertrophy on side cable of throat, the pathological signs and prevalence of mucosa congestion were obviously lower than those before treatment and the control group (P ＜ 0.05-0.01) effective rate was 88.6%.②) Improvement of microcirculation disturbance with chronic pharyngitis was evident, restoring to basically normal from medium degree abnormality before treatment, the total score values reduced to 1.941 ±0.165 from 4.836±0.242 (P ＜ 0.01).CONCLUSION: Oral negative pressure can significantly release or eliminate the symptoms and signs of chronic pharyngitis, which may relate to improvement of microcirculation disturbance.