To provide novel anti-cerebral ischemia drugs with high clinical therapeutic effect.SOLUTION: The invention provides an oxidized β-1,4-glucuronic acid oligomer represented by the formula I in the figure. The invention also provides an anti-cerebral ischemia drug, an agent for treating neuronal ischemic damage or a brain nerve-protecting medicament that contains the oligomer. [n is from 0 to 19; and m is 0, 1 or 2.]SELECTED DRAWING: Figure 1【課題】臨床治療効果の高い新規脳虚血疾患治療薬の提供。【解決手段】下式Iで表される酸化型β-1,4-グルクロン酸オリゴマー。前記オリゴマーを含有する抗脳虚血薬、ニューロンの虚血性損傷治療薬又は脳神経保護薬。[nは0~19;mは0、1又は2。]【選択図】図1