OBJECTIVETo investigate the clinical correlation between gemcitabine and thrombocytosis and its antithrombotic management strategies. METHODSTwo cases of thrombocytosis occurring in cancer patients after conventional-dose gemcitabine chemotherapy were reported. Their clinical features, underlying diseases, and drug treatment courses were analyzed in combination with a literature review. RESULTSThrombocytosis in the two patients was likely associated with the use of gemcitabine. Prophylactic anticoagulation was administered to patients at high risk of venous thromboembolism, and no thrombotic events occurred in either case. CONCLUSIONThe incidence of gemcitabine-related thrombocytosis is not uncommon, and its mechanism remains unclear. For such patients, clinical pharmacists should provide management recommendations based on platelet levels and venous thromboembolism risk to ensure medication safety and efficacy.