人工血（Artificial blood），亦作人造血，又称血液替代品（Blood substitute）或血液代理（Blood surrogates），是一种用于仿真和替代血液功能的物质。虽然它不包含血液成分，例如红血球、白血球、血小板或血浆，却能带走二氧化碳并带来氧气，直到骨髓能生产足够的红血球为止。

人工血主要有血红蛋白基氧载体（HBOCs）和全氟化碳基氧载体（PFBOCs）两大类别。

除了利用身体外的物品来造血，亦有研究利用病人本身的其他体细胞来造血。过往有把细胞还原成为iPS细胞的研究，但会增加病人患癌风险。香港苹果日报引述法新社及英国《自然》周刊新闻，在加拿大麦马士达大学的研究员迈克·巴蒂亚（Mick Bhatia）发现只要在皮肤纤维组织的母细胞加入OCT4基因，然后放入仿真细胞激素的蛋白质混合物中培育，就可以令细胞有造血功能。但预期有关研究要普及，仍然需时约5至10年。

A blood substitute (also called artificial blood or blood surrogates) is a substance used to mimic and fulfill some functions of biological blood. It aims to provide an alternative to blood transfusion, which is transferring blood or blood-based products from one person into another. Thus far, there are no well-accepted oxygen-carrying blood substitutes, which is the typical objective of a red blood cell transfusion; however, there are widely available non-blood volume expanders for cases where only volume restoration is required. These are helping doctors and surgeons avoid the risks of disease transmission and immune suppression, address the chronic blood donor shortage, and address the concerns of Jehovah's Witnesses and others who have religious objections to receiving transfused blood.