An immune booster is a food, supplement, or medication that helps to improve the body’s immune system. The immune system is a complex network of cells, tissues, and organs that work together to protect the body from foreign invaders. When the body is exposed to a virus, bacteria, or other invader, the immune system springs into action to fight off the infection. Immune boosters can be helpful for people who have a weakened immune system due to an illness or condition. They can also be helpful for healthy people who want to avoid getting sick. 

The vast majority of immune boosters work by stimulating the production of white blood cells. White blood cells are the body's primary defense against infection, so increasing their numbers can help to ward off illness. Some also contain ingredients that help to reduce inflammation, which can further protect the body from disease.

Overall, taking an immune booster can help keep you healthy during cold and flu season by reducing your risk of getting sick and helping you recover more quickly if you do get sick. They are a great way to keep your immune system functioning properly. There are many different ways to boost your immune system, but the most important thing is to find a method that works for you and stick with it. Whether you take supplements, eat certain foods, or get regular exercise, boosting your immune system can help you stay healthy and avoid getting sick.