Hello Doctors, I often get cold, fever, nose flow and some headache during winters. One stops and other starts. Is there anything that I can do to keep myself warm from inside. Can chyawanprash or some tonic helps to boost immunity during winters. I am 27/M weight 68 kg, height 5.6' inches. I really appreciate your time in answering this questions. I hope this may helps other as well. As this is a very common problem in winters.