We experienced familial occurrence of bronchiolitis obliterans (BO) associated with Sauropus androgynus. The cases were a mother and daughter and both were admitted to our hospital because of dyspnea after taking Sauropus androgynus. Both cases had hyperinflation of both lungs in chest x-ray and lung function test showed severe obstructive impairment. At first, they were given a diagnosis of severe asthma and treated as such. However, neither their symptoms nor lung function improved. They did not show any reversibility on lung function tests. Although we did not perform histological examination of the lung, they were given a diagnosis of BO associated with Sauropus androgynus (SABO), because of the following reasons. Cases of SABO in Taiwan have already been demonstrated in the 1990's, and there were no other reasons to explain their severe airflow obstruction. Neither bronchodilators nor steroid treatment improved airflow obstruction. BO is rare and can mimic asthma and chronic obstructive pulmonary disease (COPD). We should inquire about the intake of food or medication in cases suspected BO.