UNLABELLED: After withdrawal of aprotinin in 2008 only tranexamic acid (TxA, Cyclocapron, Pfitzer, Germany) remains available as antihyperfibrinolytic agent in Europe. Dosage (from 1 g to 20 g) and application strategy (single shot i.v., infusion i.v., topical) reflect an indiscriminate use of TXA in cardiac surgery. We use data analysis of three registries to evaluate safety issues and sufficiency of different TxA dosages in our center. METHODS: Registry 1: Single shot ultra-low dose TxA (1 g in priming volume). Registry 2: Single shot medium dose TxA (5 g in priming volume). Registry 3: Single shot medium dose TxA (3 g in priming volume) and continuous, weight-adapted administration during cross clamping. Independence of surgeon's preference was achieved by changing dosage every surgery day regardless of operation schedule. RESULTS: Data analysis was carried out on 1182 consecutive, elective patients (1 g TxA n = 415; 3 g + x g TA n = 367; mean TxA dose 4.4 g ± 1.0 g; 5 g TxA n = 400). Patient characteristics were well matched in all three registries (mean age: 69 ± 9.5y, BMI 28.2 ± 4.7, Creatinin 107.5 ± 52.8 µM), as were performed surgical procedures (excluding organ transplantation). Postoperative data showed no significant differences for blood loss and major adverse events (1 g vs. 3 + g vs. 5 g: blood loss: 894 ± 1479 vs. 903 ± 1282 vs. 1004 ± 1604 ml; stroke: 1.5 vs. 1.6 vs. 1.5%; myocardial infarction 2.7 vs. 3.3 vs. 1.3%; 30d mortality 3.9 vs. 4.2 vs. 4.8%, respectively). Secondary endpoints (de novo dialysis, transfusion requirement, ICU and total treatment time) showed no significant differences between registries. CONCLUSION: Use of 1 g TxA is safe and sufficient for elective patients with on pump cardiac surgery and thus has been established as strategy of choice in our center.