The histologic evidence of amiodarone pulmonary toxicity is interstitial pneumonia with foamy alveolar macrophages, which ultrastructurally show lamellar inclusion bodies due to lipid storage. Bronchoalveolar lavage (BAL) fluid findings include foamy macrophages, considered characteristic, and, in certain patients, differential cell counts suggestive of active alveolitis, giving rise to an immunologic explanation for its origin. The present study was undertaken in order to investigate the findings in BAL fluid in nontoxic patients taking amiodarone and to evaluate their clinical relevance. Eleven patients taking amiodarone chlorhydrate for severe ventricular arrhythmias (345 +/- 129 mg/day during 46 +/- 31 months and an accumulated dose of 440 +/- 337 g) and without clinical or radiological evidences of pulmonary toxicity, were clinically evaluated and studied by BAL. As shown in Table 1, cough and pulmonary rales were common findings (64% and 36% respectively), chest X-Rays were normal or indicative of cardiac failure and arterial blood gases showed slight hypoxemia (PaO2 83 +/- 10). As these are usual findings in advanced cardiac diseases, the patients were considered as having no amiodarone toxicity. BAL was done and the fluid obtained was processed for cytologic study. In every patient foamy macrophages were seen with light microscopy and lamellar bodies were detected by electron microscopy. In 5/10 evaluable patients BAL fluid cell count disclosed an increase in lymphocytes, leukocytes or both, indicative of alveolitis. This group of patient had lower PaO2 and PaO2/PAO2 than "non alveolitic" patients (76 +/- 9 mmHg vs 89 +/- 5 mmHg and 0.72 +/- 0.1 vs 0.85 +/- 0.08 - p less than 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)