When treating flu and colds with TCM herbs it is extremely important to determine the type of cold/flu pattern before using herbs. There are a couple formulas for colds/flu in the following link, along with a description of the symptom pattern with which they are used. The third formula (immune) on this page is to build up the immune system when well. It is a tonic formula and not to be used when sick. The first two formuas for the flu are available in Chinese teapill form and would be found in a Chinese herb store (sometimes even Chinese grocery stores carry these as they are common formulas for colds/flu when they first start).
Traditional Chinese Medicine/TCM and Cold and Flu
Here are some TCM Folk remedies for the flu. This discussion includes some ingredients which are more easily located, sometimes even some of the bulk herbs may be found in Western herbal shops:
TCM Folk Remedies for Cold and Flu
Here is a TCM video with a simple ingredients found in the grocery store remedy which may be used as a remedy for treating colds/flu.
Traditional Chinese Medicine: Cold & Flu Recipes | Expert Village Videos
Once viruses have invaded the interior of the body, more expert help is required as using the wrong herbs may drive the illness more deeply into the body. This is why the Chinese attempt to have remedies at home to nip colds/flu in the bud when they first start. I have often been able to do this myself by stocking some teapills in the refrigerator or freezer to use when illness threatens. I have averted many illnesses by doing this. If a good TCM practitioner can be located, one who knows how to use herbs to treat colds/flu, then it is possible to treat cold/flu when it has invaded the interior. It is very hard to do by oneself once it has reached this stage.
Here is another video about TCM treatment for flu--it is too bad that he did not print out the formula names for those unfamiliar with them, though at least one or two of them are mentioned above in the shen-nong page:
Traditional Chinese Medicine: Cold & Flu Formulas: Herbal Therapy in Traditional Chinese Medicine | eHow.com