Like most extracts from plant or animal origin, the constituent base for echinacea purpurea extract is complex, consisting of a wide variety of chemicals of variable effect and potency. Some chemicals may be directly antimicrobial, while others may work at stimulating or modulating different parts of the immune system.
 

Echinacea Purpurea 
 

All species have chemical compounds called phenols, which are common to many other plants. Phenyl propanoid constituents such as cichoric acid and caftaric acid are present in E. purpurea, other phenols includeechinacoside, a caffeic acid glycoside, which is found in greater levels within E. angustifolia and E. pallida roots than in other species. Many caffeic acid derivatives are ubiquitous plants constituents with little specific effects other than anti-oxidant activity.

Although the phenolic constituents are poorly absorbed and have no dose–response relationship in clinical settings, their relative proportions can serve as markers for species identification and quality control of herbal remedies. Other chemical constituents that may be important in echinacea health effects include alkylamides and polysaccharides.

As with any herbal preparation, individual doses may vary significantly in active chemical composition. In addition to poor process control which may affect inter- and intra-batch homogeneity, species, plant part, extraction method, and contamination or adulteration with other products all lead to variability between products.

Use too much can lead to a low grade fever, sensitive crowd dermatitis may occur.

Overall, Echinacea is considered safe. It is well tolerated by most people. When taken as directed, little or no toxicity is associated with Echinacea use. Echinacea may possibly be beneficial, in reducing duration and severity of symptoms. Echinacea should not be used for auto-immune disorders such as tuberculosis and leucosis. AIDS patients use of Echinacea is very controversial because not sure of its effects. Other people that should not take Echinacea are those allergic to plants in the daisy family. Prolonged use (more than eight weeks) is not recommended and may cause immune suppression or liver problems. Echinacea should not be substituted for other medical treatments in very rapid infections.

Related plant extract:

Artichoke extract, milk thistle extract, epimedium extract, white willow bark extract