A mattress cover protects your mattress from spills, dust, and bacteria. It helps keep your mattress clean and dry, which is important for health and hygiene. A high-quality mattress cover should be made from breathable, absorbent materials like polyurethane and cotton. It should absorb liquids to prevent them from reaching the mattress and trap dust and bacteria on its surface rather than letting them enter the mattress. This protects your mattress and helps prevent the growth of germs and allergens that can bother allergy sufferers.