[abhikandoi2000]

In India, it is pretty common to eat the leaves of the plant Tulsi, as it is known to improve the immune system. Personally, I used to catch cold almost 3-4 times a year, but taking Tulsi (in the form of one drop of concentrated tulsi extract mixed in my morning drinking water) has helped me immensely. The frequency with which I catch cold/fever has reduced dramatically.