Echinaceas incredible popularity is due to its well documented safe and effective immune stimulating properties. Many people use sweet Echinacea at the first signs of cold or flu. Research suggests that Echinacea be taken when needed. If you are looking for a long term immune building tonic see the astragalus extract information. For deficient conditions that require immune building see the Echinacea/Astragalus information. Available in a 1, 2 and 4 ounce liquid.