If not cleaned regularly, grout tends to generate a variety of problems that may be harmful for you. These include harmful microbes, dirt, grease, stains, and mold. Although not so harmful on face value, they are extremely unpleasant as they can produce foul odor all over your room. Mold, lime scale and mildew can also form on wall joints (mainly seen in bathrooms) causing sealing problems making your floor looking classless. And since grout is not the easiest thing to clean, the situation only gets worse with time.