To the Editor: Winterbauer et al. (N Engl J Med 294:919–921, 1976) present convincing evidence that chrysotherapy may induce diffuse pulmonary injury. We wish to re-emphasize two commonly accepted precautions in the use of chrysotherapy, pertinent to the cases reported. Phenylbutazone and gold sodium thiomalate were given concomitantly in Case 1. A number of authorities123state that pyrazolon-derived drugs (phenylbutazone, oxyphenbutazone) are interdicted during chrysotherapy. Both drugs produce bone-marrow suppression and aplasia, and one drug may enhance the toxic potential of the other.3Furthermore, the causative agent cannot be identified if mucocutaneous lesions develop during combined drug treatment, and. © 1976, Massachusetts Medical Society. All rights reserved.