传明酸（Tranexamic Acid或transamin，又称氨甲环酸）是一种人工合成的胺基酸，其他名称有断血炎、止血环酸、凝血酸等，具有止血抗炎的药理效果，本作为凝血剂用途，有针剂跟口服两种用法。

属于纤维蛋白溶解抑制药中的一类，通过可逆性阻断纤溶酶原分子上的赖氨酸结合位点，导致纤溶酶原不能转变为纤溶酶，从而有效抑制纤维蛋白溶解、产生止血作用。临床上广泛应用于外科、内科、泌尿科和妇产科等领域，治疗各种出血性疾病和手术时异常出血等。又因可以抑制黑色素细胞的活性，防止和改善皮肤的色素沉积，因而有一定的美容效果。

Tranexamic acid (TXA) is a medication used to treat or prevent excessive blood loss from trauma, surgery, and in various medical conditions including hemophilia and heavy menstrual bleeding. It comes in oral and intravenous forms.

Side effects are uncommon and include gastrointestinal effects, dizziness, fatigue, headache, and hypersensitivity reactions. This medication needs to be used cautiously in people with kidney disease and who are at a high risk for blood clots. Tranexamic is safe to use in pregnant women. However, caution should be used in lactating women. It is an antifibrinolytic.