Haloperidol is an antipsychotic drug belonging to the butyrophenone derivatives. Being an antagonist of D2 receptors, it inhibits dopamine-dependent transmission. The authors present the case of a 49-year-old female patient with a diagnosis of triple-negative breast cancer at the disseminated stage. The patient presented to the hospital for planned chemotherapy, however, due to increased dyspnea, was referred to the Department of Oncology at the University Hospital in Krakow for expanded diagnosis. An urgent CT scan was performed, which showed an image of a hydropneumothorax and raised a suspicion of pleural abscess. Antibiotic therapy and oxygen therapy were implemented, however, due to the insufficient control of symptoms, the patient was transferred to the Clinical Department of Palliative Medicine at the University Hospital in Krakow. Four days before the patient’s death, there was a significant deterioration in pain control, an increase in dyspnea refractory to oxygen therapy, anxiety symptoms, disorientation, the appearance of terminal agitation and unresponsiveness to administered midazolam. After the implementation of haloperidol, a rapid, significant improvement in the control of the of the patient’s symptoms occurred, giving hope for the wider use of this drug in patients who have developed a refractory to standard pharmacotherapy exacerbation of cancer symptoms.