This study is a Phase III, double blinded, randomized, placebo controlled, crossover trial testing the efficacy of thalidomide in suppressing the chronic cough of IPF. All subjects will be randomized to either begin the study receiving the active study drug - (thalidomide) or inactive drug (placebo). Study drug will be administered in escalating dose starting at 50 mg a day increasing to 100 mg a day if cough is still present after 2 weeks. Study drug will be taken by mouth at bedtime. Patients will remain on their initial treatment for 12 weeks. After 12 weeks of treatment, the subjects will be administered the Cough Specific Quality of Life Questionnaire (CQLQ), a visual cough analogue scale, and St. Georges Respiratory Questionnaire (SGRQ). In addition, investigators will collect the subjects cough diary. After 12 weeks of treatment all subjects will enter a 2 week wash-out phase in which all drugs will be discontinued. After the 2 week wash-out phase, all subjects will again be administered the Cough Specific Quality of Life Questionnaire (CQLQ), a visual cough analogue scale, and St. Georges Respiratory Questionnaire (SGRQ). In addition, investigators will collect the subjects cough diary. All subjects will then be crossed over to the other treatment arm for an additional 12 weeks of treatment. After the second 12 weeks of treatment, the subjects will be administered the Cough Specific Quality of Life Questionnaire (CQLQ), a visual cough analogue scale, and St. Georges Respiratory Questionnaire (SGRQ). In addition, investigators will collect the subjects cough diary.
