This herb is found in many supplements used to build up the immune system. I've used Yu Ping Fen Wan, a chinese formula mostly containing astragalus, for three years now (I take it only in the winter months) and have only had one 3-day cold! This in spite of teaching 100 snuffling sneezy college students daily. But my respect for the herb increased considerably when I read this abstract posted on our U.S. National Institute for Health website. Turns out it appears to benefit parkinson's:

http://www.ncbi.nlm.nih.gov/pubmed/19409437
Neuroprotective effects of Astragaloside IV in 6-hydroxydopamine-treated primary nigral cell culture.
Chan WS, Durairajan SS, Lu JH, Wang Y, Xie LX, Kum WF, Koo I, Yung KK, Li M.
Source

School of Chinese Medicine, Hong Kong Baptist University, Kowloon Tong, Hong Kong.
Abstract

Parkinson's disease (PD) is caused by a progressive degeneration of dopaminergic neurons in the substantia nigra. Oxidative stress and neural degeneration are suggested to be involved in the pathogenesis of Parkinson's disease. In the present study, Astragaloside IV (AS-IV) extracted from the dried root of Astragalus membranaceus, a well-known Chinese medicine used for the treatment of neurodegenerative diseases, was investigated for its capacity to protect dopaminergic neurons in experimental Parkinson's disease. By examining the effect of AS-IV on 6-hydroxydopamine (6-OHDA)-induced loss of dopaminergic neurons in primary nigral culture, we found that AS-IV pretreatment significantly and dose-dependently attenuated 6-OHDA-induced loss of dopaminergic neurons. Neuronal fiber length studies showed that massive neuronal cell death with degenerated neurons was observed in those cultures incubated with 6-OHDA, whereas in AS-IV co-treatments most dopaminergic neurons were seen to be intact and sprouting. In flow cytometric analysis, AS-IV resulted in a marked and dose-dependent rescue in tyrosine hydrolase (TH)-immunopositive cells from 6-OHDA-induced degeneration of dopaminergic neurons. Double immunofluorescence revealed that AS-IV treatment alone at concentrations of 100 and 200 microM increased the level of TH and NOS (nitrite oxide synthase) immunoreactivities; however, the protective effect of AS-IV on TH and NOS immunopositive cells in 6-OHDA treated nigral cell cultures was only seen at a concentration of 100 microM. These findings show that AS-IV can protect dopaminergic neurons against 6-OHDA-induced degeneration. Besides the neuroprotective effect, AS-IV alone promoted neurite outgrowth and increased TH and NOS immunoreactive of dopaminergic neurons. The neuroprotective and neurosprouting effects of AS-IV are specific for dopaminergic neurons and it has therapeutic potential in the treatment of PD.

I can't help but notice this is another research study where they pre=treated the subjects with the substance being tested. Why? No one in the world is given a rather large amount of a single ingredient and then dx'd with PD later, so why do they do the study that way?

I would respect this type of study much more if the subjects were lesioned first and THEN given the astralagus (or test subject of the day).

Having said that, I'm glad this seems to be working for you, at least in the cold department. We may give it a try ourselves for that reason alone. Thanks for bringing this to our attention.