Sir.—Cystic fibrosis (CF) is the most common genetic disease affecting children in the United States, with an incidence of one per 2000 whites and one per 17 000 blacks.1 In 1982 only 2.6% of the 13 487 patients added to the registry of the Cystic Fibrosis Foundation were black.2 Although a variety of gastrointestinal tract complications has been reported in patients with CF,3 an Clinical Features of Three Black Patients With Cystic Fibrosis and Peptic Ulcer Disease* Patient/Sex CF Presentation Subsequent Clinical Findings Ulcer Presentation Status at Last Evaluation 1/M 2/F 3/M At age 8 y; mild asthma; nasal polyps; sweat chloride:112, 88 mEq/L (mmol/L) (normal <60) At age 23 y; hemoptysis; sweat chloride: 64, 70 mEq/ L (mmol/L) At age 18 y; chronic cough; hemoptysis; sweat chloride: 149,84, 112 mEq/L (mmol/L) Opacification of paranasal sinuses; digital clubbing; decreased pulmonary function Steatorrhea; opacification of paranasal