Prevention of common colds with Andrographis paniculata dried extract. A Pilot double blind trial

In a randomized placebo-controlled double blind study, the possible preventive effect against common colds of Kan Jang tablets made from Andrographis paniculata (Barm. F.) (Nees) dried extract was tudied during the winter season. The study was carried in a rural school. The students were divided in two groups, of which Group 1 (n=54), received 2 tablets of Kan Jang per day and Group 2 (n=53), 2 tablets of a placebo (P) per day during three months. The individuals were evaluated weekly by a clinician who diagnosed the presence or absence of common colds during the three months. The analysis of the occurrence of colds revealed that the administration of Kan Jang after the first month did not produced any significant difference. However, after the third month of intake of Kan Jang there was a significant decrease in the incidence of colds as compared to the placebo group. The rate of incidence of colds among the students treated with Kan Jang was 30% (16/54) compared to 62% (33/53). The relative risk of catching a cold was therefore 2.1 (1.32-3.33, 95% confidence interval) times lower for the Kan Jang group. The attributable protective effect of Kan Jang was 33%. The results suggest that Kan Jang tablets have a preventive effect against common colds during the winter period.