BACKGROUND: An unintended bolus is delivered by the syringe pump if intravenous line occlusion is released in an inappropriate manner. OBJECTIVE: The aim of this study was to measure the amount of flushed fluid when an occlusion is inappropriately released and to assess the effect of different syringe pump settings (flow rate, alarm setting, size of syringe and syringe pump model) on the flushed amount. METHODS: After the stopcock was closed, infusions were started with different model syringe pumps (Terufusion® TE312 and TE332S), different syringe sizes or at different alarm settings. After the occlusion alarm sounded, the occlusion was released and the amount of fluid emerging from the stopcock was measured. RESULTS: The bolus was significantly lower when the alarm was set at a low-pressure setting. The bolus was significantly lower with a 10-ml than a 50-ml syringe. A significant difference was seen only when a 50-ml syringe was used (TE312: 1.99 ± 0.16 ml vs. TE332S: 0.674 ± 0.116 ml, alarm High, p < 0.001). CONCLUSION: To minimize the amount of accidentally injected medication, a smaller syringe size and a low alarm setting are important. Using a syringe pump capable of reducing the inadvertently administered bolus may be helpful.