Andrographis paniculata and prevention of upper respiratory infection:
Andrographis paniculata may be effective in cold prevention. According to one double-blind, placebo-controlled study, andrographis paniculata (kan jang) may increase resistance to colds. In a 3-month-long trial 54 of the participants took two 100-mg tablets standardized A. paniculata daily. The other 53 students were given placebo tablets. Then, once a week throughout the study, a clinician evaluated all the participants for cold symptoms. No significant differences between the groups were observed after 1 month. By the end of the trial however, only 16 people or 30% in the group using A. paniculata had experienced colds, compared to 33 of the placebo-group participants or 62%. This difference was statistically significant, indicating that A. paniculata reduces the risk of catching a cold by a factor of two as compared to placebo. (6)