Dyspnea is a common symptom among patients with gastrointestinal cancer, and a comprehensive evaluation of their respiratory function is essential. Self-reporting aids in the assessment of the degree of dyspnea, while objective examination methods are performed to identify the potential underlying causes when subjective symptoms are present. Standard treatment protocols should be followed for potentially reversible and common causes of dyspnea, such as pleural effusion, pneumonia, airway obstruction, anemia, asthma, exacerbation of chronic obstructive pulmonary disease, pulmonary thromboembolism, or drug-induced interstitial lung disease. Careful and close monitoring is required due to the high frequency of pulmonary thromboembolism and the risk of cardiovascular accidents, drug-induced interstitial lung disease, or other complications from some anticancer drugs. In case of hypoxemia with an oxygen saturation of 90% or less, palliative treatment should comprise standard oxygen therapy such as nasal cannula, mask, or high-flow nasal cannula. If non-pharmacological oxygen therapy is not effective, pain control through systemic narcotic analgesics and anti-anxiety therapy with benzodiazepines may be helpful.