We report an instructive case of minocycline-induced eosinophilic pneumonia confirmed by re-challenge test, in which a preceding lymphocyte-stimulation test indicated acetaminophen as the etiologic agent. A 55-year-old woman developed high fever and lung infiltrates with pulmonary eosinophilia after exposure to minocycline, acetaminophen, theophylline and procaterol. All of the medicines were discontinued, resulting in prompt improvement. The lymphocyte stimulation tests provided a positive result for acetaminophen, but not for the other medicines; however, a negative result was given by a re-challenge test with acetaminophen. In contrast, symptoms and hypoxemia reappeared when minocycline was re-administered. We would like to emphasize that lymphocyte stimulation test results need to be carefully interpreted for individual drugs.