主题：顺势疗法的 “类似法则”

史蒂芬·巴雷特（Stephen Barrett）

顺势疗法的支持者把其基本原则称作“类似法则”，“同类可以治愈同类”，即如某物质能够导致健康人产生某些症状，那么该物质就能治愈具这些症状的疾病。这种观念是感应巫术（sympathetic magic）的一种形式，感应巫术类似于吃狮子的心会使人勇敢这种原始观念。

顺势疗法的创始人，塞缪尔·哈内曼（Samuel Hahnemann）医生,据说他的理论是根据他摄食金鸡纳树皮的实验，金鸡纳树皮含有用来治疗疟疾的奎宁。服食之后，他体验到了与疟疾同样的症状：口渴、头脑中有悸动感还有发烧。他确定，药物治愈疾病的效力来源于它能够产生同疾病相似的症状。他和他的早期信徒用草药、矿物和其它物质在健康人包括他们自己身上做了验证，并且保留了详细的观察记录。

验证过程中报告的症状被编成冗长的参考书叫做药物学（materia medica），被信徒们奉为圣经。然而，大部分的验证都是在100到200年前做的，当时医学科学尚处于婴儿期。那时对健康和疾病的性质，以及对如何进行实验把原因和结果从巧合中分离出来，都知之甚少。

服食某物后产生症状这个事实可以有好多种解释。在某个具体的日子，许多人都会有很偶然的不愉快的想法和躯体感受。要判断某个物质是否确切地导致某个症状，必须把服食某物质的人同服食对照物质的人加以比较。为了防止偏倚，实验者和受试者都不能知道吃了什么。

用于编著药物学书的验证过程都没有使用这些方法。服食物质的剂量、时间、纪录数据的方式等都很不一样，而且都没有对照。所以，要确定报告的症状是否真的与服食实验物有关是不可能的。另外，许多症状可能被暗示产生。

《实验药物学字典》这本常用的三卷一套的书，是由约翰·亨利·克拉克医生写的，是说明验证过程之愚蠢的例子。这本书约有2500页，描述了服食约 1200种物质后臆想报告的症状。许多描述包含100多个述说，意味着症状的数目超过20万。这本书没有说明这些原始的验证是什么时候做的、如何做的、以及谁报告了这些详细的发现。所以不可能认证这些研究是否真的做了，是谁做的，有关发现的报告是否准确。

列出的许多症状都很奇怪。Lac felinum有“不能忍受她原来喜爱的蛤蜊的气味。”Lacrodectus mactans有“可怕的尖叫声，声称她呼吸困难就要死了”。Magnesia sulphurica有“迟钝”。Oleum animale有“耳朵听到唱歌声、叮当声和嗡嗡声”。Natrum carbonicum有“早晨匆忙起床”。有些列出的症状明显地发生在身体的一侧，比如“左睾丸难受”。所有这些，都想象为对确定病人是否“适用”某种专门药剂是有用的。

即使这些验证报告是始终一致的，产生症状的物质能够治愈相同的症状也没有合乎逻辑的道理。通过良好设计过的实验，没有任何证据表明“类似法则”在起作用。试验物质作用的真正途径是试验它是否对病人有帮助。这需要临床试验，把服食试验物质的人群与没有服食的人群相比较。没有一个顺势疗法的产品被证明是有效的，绝大多数的产品甚至从来没有进行过临床试验。

Homeopathy's "Law of Similars"
Stephen Barrett, M.D.

Proponents call homeopathy's defining principle the "Law of Similars." ("Like cures like.") This holds that substances that cause healthy people to get symptoms can cure diseases that have these symptoms. This idea is a form of "sympathetic magic" similar to the primitive idea that eating the heart of a lion will make a person brave.

Homeopathy's founder, Samuel Hahnemann, M.D., is said to have based his theory on an experience in which he ingested cinchona bark, the source of quinine used to treat malaria. After taking it, he experienced thirst, throbbing in the head, and fever -- symptoms common to malaria. He decided that the drug's power to cure the disease arose from its ability to produce symptoms similar to the disease itself. He and his early followers then conducted "provings" in which they administered herbs, minerals, and other substances to healthy people, including themselves, and kept detailed records of what they observed.

The symptoms reported during provings have been compiled into lengthy reference books called materia medica, which proponents regard as gospel. However, most of the provings were done between 100 and 200 years ago, when medical science was in its infancy. Very little was known about the nature of health and disease or about how to conduct experiments that separate cause and effect from coincidence.

The fact that a symptom occurs after taking a substance can have several explanations. During a typical day, most people experience occasional unpleasant thoughts and bodily sensations. To determine whether a substance actually causes a symptom, it would be necessary to compare people who receive the substance with people who receive a control substance. To guard against bias, neither the experimenters nor the test subjects should know who gets which.

The provings used to compile materia medica were not conducted in this manner. There were wide variations in the amounts of substances administered, the timing of the administrations, the way in which data were recorded, and the length of the studies -- and there were no controls. Thus it is impossible to know whether the reported symptoms were actually related to administration of the test substances. In addition, many symptoms may have resulted from suggestibility of the test subjects.

"A Dictionary of Practical Materia Medica," a widely used 3-volume set authored by John Henry Clarke, M.D., illustrates the foolishness involved in provings. The book contains about 2,500 pages that describe the symptoms that supposedly were reported following administration of about 1200 substances. Most descriptive pages contain more than 100 claims, which means that total number of symptoms exceeds 200,000. The book does not indicate when or how the original "provings" were done or who reported most of the specific findings. Thus it would be impossible to examine whether the studies were properly done, who did them, and whether the findings were accurately reported.

Many of the listed symptoms are odd. Lac felinum includes "Cannot bear the smell of clams, of which she is naturally fond." Lacrodectus mactans includes "Screams fearfully, exclaiming that she would lose her breath and die." Magnesia sulphurica includes "stupidity." Oleum animale includes "Singing, tinkling, and buzzing in ears." Natrum carbonicum includes "hurries out of bed in the morning." Some listings include symptoms that occur predominantly on one side of the body, such as "sickening sensation in left testicle." All are supposedly useful in determining whether the patient might "fit" a particular remedy.

Even if the proving reports were consistent, there is no logical reason why substances that could produce symptoms should cure such symptoms. Nor is there evidence from appropriately designed studies that the "law of similars" actually operates. The real way to test something works is to test whether it helps sick people. This requires clinical trials in which people who get the test substance are compared with people who do not. No homeopathic product has ever been proven effective; and the vast majority of products have never even been clinically tested.