In oncologic patients, emotional distress and psychiatric disorders are frequently observed, often leading to increased consumption of sedative substances such as alcohol and benzodiazepines, as well as analgesics, including opioids. Prolonged or excessive use of these agents may result in the development of substance use disorders. Alcohol intake, in particular, is associated with increased risk of alcohol-related cancer, making a history of alcohol, benzodiazepines, and opioid use common among oncology patients. Substance withdrawal syndrome is a recognized indication for Intensive Care Unit (ICU) admission, either as a primary diagnosis or as a complicating factor during hospitalization. Given the rising number of cancer patients requiring ICU care due to improved overall survival, intensivists must be equipped to identify and manage withdrawal syndromes in this population. Diagnosis is based on clinical findings, and initial management should follow the assessment of Airway, Breathing, and Circulation (ABC). Pharmacologic treatment typically involves symptom-triggered therapy, substitution with a long-acting agent, replacement for the abused substance, followed by gradual tapering, treatment of underlying diseases, and the development of a long-term management strategy. With an early diagnosis and appropriate management, withdrawal syndromes are rarely life-threatening diseases. It is crucial that intensive care physicians remain vigilant, competent in recognizing the clinical features, and prepared to treat these syndromes effectively. This chapter provides a comprehensive review of the incidence, pathophysiology, clinical presentation, management, and prognosis of withdrawal syndromes related to opioids, benzodiazepines, and alcohol.