The Status of Homeopathy Research
Most analyses of the research on homeopathy have concluded that there is little evidence to support homeopathy as an effective treatment for any specific condition, and that many of the studies have been flawed. However, there are some individual observational studies, randomized placebo-controlled trials, and laboratory research that report positive effects or unique physical and chemical properties of homeopathic remedies.
Research Challenges
Homeopathy is difficult to study using current scientific methods because highly diluted substances (known as ultra-high dilutions or UHDs) cannot be readily measured, making it difficult to design or replicate studies. In addition, homeopathic treatments are highly individualized and there is no uniform prescribing standard for homeopaths. There are hundreds of different homeopathic remedies, which can be prescribed in a variety of different dilutions to treat thousands of symptoms. On the other hand, many aspects of the interactions between the homeopathic practitioner and his or her patients may be quite beneficial, and can be studied more easily.
Side Effects and Risks
Although the side effects and risks of homeopathic treatments are not well researched outside of observational studies, some general points can be made about the safety of these treatments:
A systematic review found that homeopathic remedies in high dilution, taken under the supervision of trained professionals, are generally considered safe and unlikely to cause severe adverse reactions...
Homeopathic remedies are not known to interfere with conventional drugs; however, if you are considering using homeopathic remedies, you should discuss this with your health care provider first.
http://nccam.nih.gov/health/homeopathy/
CONCLUSIONS: At the moment the evidence of clinical trials is positive but not sufficient to draw definitive conclusions because most trials are of low methodological quality and because of the unknown role of publication bias. This indicates that there is a legitimate case for further evaluation of homoeopathy, but only by means of well performed trials.
http://www.ncbi.nlm.nih.gov/pubmed/1825800