Abstract： This report presents a case of a 65-year-old patient with a right lower lobe adenocarcinoma of the lung,who had an exon 19 deletion mutation(E746_A750del)in the epidermal growth factor receptor(EGFR)gene and developed interstitial lung disease after taking osimertinib for 100 days.The patient improved after discontinuing osimertinib and receiving oxygen and glucocorticoid treatment.Then the patient tried erlotinib hydrochloride tablets,and interstitial lung disease did not occur again.