The invention relates to stable liquid neurotoxin formulations which are free of animal proteins, comprising a surfactant, an amino acid selected from tryptophan and tyrosine, a buffer comprising sodium, chloride and phosphate ions, which have a pH between 5.5 and 8, and which are stable for 2 months. These compositions are suitable for use in therapy and in particular for administration to a patient to achieve a desired therapeutic or aesthetic effect. The invention also relates to the use of an amino acid selected from tryptophan and tyrosine to protect a proteinaceous neurotoxin from degradation in a liquid composition which is free of animal derived proteins.本發明係關於不含動物蛋白質之穩定液體神經毒素調配物，其包含界面活性劑、選自色胺酸及酪胺酸之胺基酸、包含鈉、氯及磷酸根離子之緩衝液，該等調配物具有在5.5與8之間的pH，且其穩定2個月。此等組合物適用於治療且尤其適用於投與患者以達成所要治療或美容效果。本發明亦關於選自色胺酸及酪胺酸之胺基酸之用途，其用於保護蛋白質神經毒素在不含動物來源之蛋白質的液體組合物中免遭降解。
