Spoiled cheese can make you sick. According to MedlinePlus, dairy products that have not been properly refrigerated can be a potential cause of food poisoning.
According to DCI Cheese Company, hard or processed cheeses take much longer to spoil than soft cheese, such as ricotta. This company advises throwing away cheese when mold develops on the inside of the cheese or when the aroma of the cheese changes from the way it smelled when the cheese was purchased. It is safe to eat cheese that has developed surface mold as long as the mold is removed before the cheese is eaten.