In Chinese Medicine, tonic herbs help to strengthen and increase our Qi, and in turn our vitality and immunity.
So if we are infected with a pathogen, all of our resources (Qi and Blood) are working to fight it. During an acute sickness (cold/flu), tonic herbs can potentially strengthen the pathogen so the general rule is to avoid when you are acutely very sick Once you have moved past the acute symptoms of sickness, then it’s great to bring in the tonic herbs and medicinal mushrooms again Reishi and Cordyceps are the exception as they can clear phlegm, which is usually present in a cold or flu type sickness.