There are nine known species of echinacea, all of which are native to North America. They were used by Native Americans of the Great Plains region as traditional medicines.
Echinacea is used as a dietary supplement for the common cold and other infections, based on the idea that it might stimulate the immune system to more effectively fight infection. Echinacea preparations have been used topically (applied to the skin) for wounds and skin problems.
The roots and above-ground parts of the echinacea plant are used fresh or dried to make teas, squeezed (expressed) juice, extracts, capsules and tablets, and preparations for external use. Several species of echinacea, most commonly Echinacea purpurea or Echinacea angustifolia, may be included in dietary supplements.
How much do we know?
Many studies have been done on echinacea and the common cold. Much less research has been done on the use of echinacea for other health purposes.
What have we learned?
Taking echinacea after you catch a cold has not been shown to shorten the time that you’ll be sick.
Taking echinacea while you’re well may slightly reduce your chances of catching a cold. However, the evidence on this point isn’t completely certain. Currently, the National Center for Complementary and Integrative Health (NCCIH) is funding research to identify the active constituents in echinacea and to study the effects on the human immune system of substances in bacteria that live within echinacea plants.
What do we know about safety?
There are many different echinacea products. They may contain different species of plants or different parts of the plant, be manufactured in different ways, and have other ingredients in addition to echinacea. Most of these products have not been tested in people.
For most people, short-term oral (by mouth) use of echinacea is probably safe; the safety of long-term use is uncertain.
The most common side effects of echinacea are digestive tract symptoms, such as nausea or stomach pain.
Some people have allergic reactions to echinacea, which may be severe. Some children participating in a clinical trial of echinacea developed rashes, which may have been caused by an allergic reaction. People with atopy (a genetic tendency toward allergic reactions) may be more likely to have an allergic reaction when taking echinacea.
Current evidence indicates that the risk of interactions between echinacea supplements and most medications is low.
Tell all your health care providers about any complementary or integrative health approaches you use. Give them a full picture of what you do to manage your health. This will help ensure coordinated and safe care.
Source: Herbs at a Glance. https://nccih.nih.gov/health/echinacea/ataglance.htm.