Objective: To observe clinical effect of the best decoction time of Yinqiao San and influence to peripheral blood T lymphocytes subpopulations in treating acute upper respiratory infection. Method: One hundred and twenty-two patients were randomly divided into control group (62 cases) and experimental group (65 cases) by random number table

patients in control group received Yinqiao San for 12 minutes' boiling

patients in experimental group received Yinqiao San for 6 minutes' boiling

200 mL/dose

and according to state of an illness

100 mL/time

2-4 times/day. Courses of treatment were 3 days. And onset time of hypothermia and tiem of fever were observed. Before and after treatment

scores of traditional Chinese medicine(TCM) syndrome was graded. Levels of T lymphocytes subpopulations were also detected for safety evaluation. Result: The revealing rate of observation group was 69.23%

which was higher than that was 51.61% in control group (P<0.05). At the third and sixth hours after taking drugs

the temperature of observation group was lower than that in control group (P<0.05). The onset time and antipyretic time in observation group were both shorter than these data in control group (P<0.05). After treatment

Scores of sore throat

head pain

stuffy nose

bad wind in observation group were inferior to the scores in control group (P<0.01). The levels of CD3+ CD4+

and CD4+/CD8+ in observation group were superior to the levels in control group (P<0.05). While the CD3+ CD8+ standards in observation group were lower than these in control group (P<0.05). Conclusion: At the sixth minute after boiling

the Yinqiao San can treat acute upper respiratory infection (the wind heat invading syndrome)

improve symptoms and clinical effects. Its immunoregulation was superior to the Yinqiao San which was at the twelfth minute after boiling. Thus

the best time for Yinqiao San boiling was about six minutes after elixation.