Pleuroplumonary fibrosis is an uncommon but potentially serious adverse effect of bromocriptine used in the treatment of Parkinson's disease. Two cases of this reaction, which occurred 12 months and 5 months respectively after commencing therapy are here reported. In both instances prompt clinical and radiological improvement occurred when bromocriptine intake was ceased. Fibrotic reactions to bromocriptine may be mediated by a serotonergic mechanism. Periodic monitoring of pulmonary symptoms is warranted in patients receiving bromocriptine treatment for Parkinson's disease.