Who should not take echinacea?

Echinacea is not recommended for use by people with multiple sclerosis, white blood cell disorders, collagen disorders, HIV/AIDS, autoimmune disorders, or tuberculosis.
Before taking echinacea, talk to your doctor, pharmacist, or health care professional if you have allergies (especially to plants), have any medical condition, or if you take other medicines or other herbal/health supplements. Echinacea may not be recommended in some situations.


http://www.drugs.com/mtm/echinacea.html