Echinacea (purple coneflower) was “discovered” in the late 1800’s  and regarded since as a great immune booster
There are a lot of immune-boosting herbs and they work in different ways. The way echinacea works is really interesting.
First, it contains echinacoside, a natural antibiotic that works the same as penicillin; so it can kill a broad range of viruses, bacteria, fungi, and protozoa. This makes it a really valuable herb to have around for wound healing and sick dogs. Echinacea also contains echinacein, which protects against germ attacks. When your dog is exposed to things like kennel cough or bacteria it would be a good idea to give it Echinacea to power up its immune system.