Echinacea While Breastfeeding
There haven't been sufficient scientific studies conducted on the effects of herbs and mother's milk. Almost everything a mother ingests will enter her milk supply and may affect the nursing baby. Some herbs are beneficial while others may have adverse reactions.
In all likelihood, an herb like echinacea is probably absorbed in such minute quantities that it is essentially harmless. However, it is best to err on the safe side and so conventional medical wisdom suggests you avoid taking it while nursing.