Tyrosine kinase inhibitors (TKIs) targeting BCR/ABL such as imatinib, nilotinib, dasatinib, bosutinib and ponatinib have revolutionised the management of patients with chronic myeloid leukaemia (CML) [1]. Pleural effusions and pulmonary arterial hypertension (PAH) have been reported in patients treated with these agents [2][3][4]. These side-effects are more frequently observed with dasatinib use, with partial or complete reversibility after drug withdrawal [3]. Bosutinib is a second-generation TKI prescribed in case of intolerance or resistance to imatinib, nilotinib or dasatinib. In the present report, we describe two cases of worsening of dasatinib-induced PAH and two cases of severe pleural effusions, suggesting overlapping pulmonary toxicity of bosutinib and dasatinib.Patient 1, a 44-year-old Caucasian woman with CML, was successively treated with hydroxycarbamide, imatinib, nilotinib and dasatinib. After 3 years on dasatinib, she complained of exertional dyspnoea, New York Heart Association functional class (NYHA FC) II. Echocardiography showed a dilated right ventricle and an estimated systolic pulmonary artery pressure (PAP) of 80 mmHg. Right heart catheterisation demonstrated pre-capillary pulmonary hypertension (mean PAP 34 mmHg, pulmonary capillary wedge pressure (PCWP) 9 mmHg, cardiac index (CI) 3.8 L·min