A lot has been said about rugs or carpets causing or worsening allergies; however, the rug itself is not usually at fault. Rugs can in fact reduce allergies because the fibers in them act as a filter trapping the allergens and keeping them out of the air that you breathe. Then, cleaning your rug regularly reduces the allergens in your home.
A small percentage of people are actually allergic to the fibers of the rug, such as wool, cotton or nylon, but the majority of people will actually be better off keeping their rugs, provided that they are maintained regularly.
To learn more about how often you should clean your rugs read this.