How much achinacea/goldenseal is safe for a sore throat?

None would be best. There is little if any proven value to the use of echinacea in the treatment of infection. Why spend money for something which is not likely to alter the course of your illness? If the sore throat persists, or you have reason to believe it may be bacterial rather than viral, see your family doctor and get treated appropriately.
Herbs for sore throa. As long as there is no allergy to the ingredients, then one dose three times per day is usually safe.

Related Questions

Can echinacea cause fever, sore throat, sores/ hives on mouth. Finger, foot, and genitalia?

Might be allergic! Recently this thought-to-be harmless natural health aid has been linked to some severe allergic reactions including anaphylaxis which can be life-threatening. Hives sound like a bad sign that you are, indeed, allergic to something and this could be it. So do not use it. Talk to a provider - allergy specialist if possible - but for now just don't use it. Be safe! Be well. Best wishes. Read more...
Reaction. Stop taking it if you notice difficulty breathing and or any rash. Talk to your local pharmacist to see if your problems relate to any noted side effects of echinacea. . Read more...
Not likely. But this plant is related to ragweed and may cause allergic reactions of various sorts. You probably have something else and need a DR. Echinacea is useless even when honestly dispensed. When commercial preparations are analyzed, they usually contain something other than labeled. Don't believe the rediculous claims by unscrupulous, ignorant people selling this to suckers. Read more...