As of 2015, herbs that boast the ability to support or enhance a healthy immune system in humans, including aloe vera, echinacea, ginseng, garlic and licorice root, have not been scientifically or medically substantiated, according to Harvard Health Publications. Scientists continue to research the potential immune support properties of herbs.
There is some evidence that aloe vera has healing properties for wounds, burns, frostbite and skin inflammation, according to Harvard Health Publications. It has been determined that aloe vera is not effective in treating breast tissue following radiation therapy.
Echinacea is popularly thought of as an herb that prevents or alleviates the onset of the common cold; however, in some noteworthy studies, echinacea didn't affect the duration, severity or rate of cold infections, states Harvard Health Publications. There are potential side effects for taking it. Individuals with allergies to ragweed may have a severe reaction, including anaphylactic shock. Injections of echinacea are particularly risky.
Studies conducted on garlic show that it may have the ability to fight certain bacteria, fungi and viruses, according to Harvard Health Publications. In a study conducted in southern European populations, a potential correlation was found between frequently eating garlic and onion and a reduced risk for various common cancers.