顺势疗法(Homeopathy 英语发音：/ˌhoʊmiˈɒpəθi/)，为一种替代疗法。此于1796年由山姆·赫尼曼按其以同治同理论所创。此理论指如某物质能在健康的人身上，引起病人患某病时的病症，将此物质稀释震荡处理后就能治疗该病症。此疗法为伪科学，意指错误被认为是科学的信仰系统。顺势疗法对任何病症均无作用，大型研究均发现顺势疗法不比安慰剂有效，指出疗程带来的任何正面感觉，只不过为安慰剂效应及人体的自然康复。

赫尼曼相信人生病的主因为一种他名为“病荫”的现象，而顺势疗法则为对付其而生。当时疗剂以反复以水或酒精稀释一特定物质制作。采用此制法，是因所使用的物质的多具毒性，固以稀释以降低毒性。通常以一比十或一比一百之比例，与水、乙醇反复稀释（亦可与乳糖研磨）。赫尼曼晚年使用更高稀释倍数，认为更高的稀释度，反而增强其效力，能带出物质“隐秘、幽灵般的力量”，从而产生疗效。稀释通常持续到原物质的分子消失无踪的程度，即溶夜中完全不含有原来稀释的物质。顺势疗师以参考书选取疗剂，并以病者的征状，人格物质，生理心理状况及生活史作补充考虑。

Homeopathy (/ˌhoʊmiˈɒpəθi/) is a system of alternative medicine created in 1796 by Samuel Hahnemann, based on his doctrine of like cures like (similia similibus curentur), a claim that a substance that causes the symptoms of a disease in healthy people would cure similar symptoms in sick people. Homeopathy is a pseudoscience – a belief that is incorrectly presented as scientific. Homeopathic preparations are not effective for treating any condition; large-scale studies have found homeopathy to be no more effective than a placebo, suggesting that any positive feelings that follow treatment are only due to the placebo effect and normal recovery from illness.