Pulmonary scleroderma strikes all races and is most prevalent among women during their child-bearing, child-rearing, and working years. A positive outcome from this trial, demonstrating that oral cyclophosphamide has a beneficial effect on pulmonary fibrosis, would be of great importance by offering a scientific basis for treatment. Similarly, a negative result, demonstrating no benefit from cyclophosphamide therapy, would also be important in avoiding hazardous and expensive therapy that is now being used widely.