A gastroenterologist recently recommended me to take echinacea for immune support, recommending taking it for 3 months. however, i read that you shouldn't take it more than 6 to 8 weeks. is it safe to take it for such a long period of time?

There is lack of objective evidence that taking Echinacea will do you any good. For healthy diet: http://www.choosemyplate.gov/., exercise 30 minutes/day, drink enough water daily so your urine is mostly colorless, have safe sex, no tobacco alcohol weed or street drugs. Get HPV and Covid vaccines. Wish you good health!

Depending on the type of Echinacea, it has been shown to be safely taken up to 6 months. Stomach upset is the most common side effect. Shorter periods of time are preferred because we are not sure why (or whether) it prevents infections or if it even does at all. It should not be unsafe if you take it under your doctor’s supervision.