針刺治療長久以來一直被界定為“安全易行”的治療手段，但這個特點並不是絕對的，只是相對於某些療法而言。應用針刺治療慢性疾病，其療程可能達數週至數月以上，對局部正常肌肉、血管、神經產生損傷的機會相對增加。理想的毫針，應該是進針容易，痛楚最少，對皮下組織、器官傷害性最小（安全性最高）的毫針。但最重要的前提是要能兼顧臨床療效。本研究為探討不同針尖規格對針刺鎮痛效果之影響。將ICR 系雄性小白鼠60 隻，隨機分成三組（每組20 隻）；分別是接受尖針加電針刺激之' 尖針組' ，鈍針加電針刺激之' 鈍針組' ，及未接受針刺的對照組。實驗穴位是雙側足三里穴。鎮痛療效評估以醋酸扭體鎮痛實驗模組評估不同針尖規格對鎮痛效果之影響。本研究結果顯示，無論是尖針組或是鈍針組皆較對照組明顯減少因疼痛引發的扭體反應的次數（p < 0.05 ），但尖針組與鈍針組小白鼠扭體的次數並無顯著差異（p > 0.05 ）；表示電針刺激足三里穴確有鎮痛作用。這種鎮痛效果並不會因為針尖的尖或鈍而有顯著差異。實驗結果證明針尖的適度改良（鈍化）並不會影響進針及止痛效果。Acupuncture is commonly considered a safe therapeutics. However, this impression is not correct. It usually takes a few weeks or even months to treat some chronic diseases using the acupuncture. Therefore, damages in the muscles, the blood vessels, and the nerves caused by the acupuncture needles are inevitable. A good acupuncture needle as penetrated into the muscle should have a tip causing least pain and damage and having promising therapeutic effects. We therefore used different tip sizes of acupuncture needles and investigated their anesthetic effects in this study. Sixty ICR male mice were randomly divided into three groups (20 for each group), the group receiving no treatment, the group of sharp needle tip (SNT), and the group of blunt needle tip (BNT) used in the treatment of electro-acupuncture on both the Zusanli (ST 36) acupoints of the mice. The writhing response test was used to evaluate the anesthetic effects in the three groups. As a result, both the SNT and the BNT groups significantly decreased the twisting responses as compared to the controls (p < 0.05), but no significant differences between the SNT and the BNT groups (p > 0.05). This finding suggest that the treatment of electro-acupuncture on Zusanli acupoint could induce anesthetic effect and this effect would not be affected by the tip sizes of the acupuncture needles.