A lot. Just search in PubMed (https://www.ncbi.nlm.nih.gov/pubmed/) for "homeopathy in vitro" or "homeopathy in vivo".
Please let me add, be wary though, homeopathy is generally viewed as a form of pseudoscience as it is not unusual to find the words "faith" and "homeopathy" together, and by definition, faith is the belief in something without sufficient evidence. Since evidence is the basis for science, it is specially important to be critic of the methodology, results and the interpretation of results - both for and against - homeopathy.
Personally I have my doubts concerning this subject, but maybe this review of RCT's of homeopathic treatment is what you are looking for. The group of Mathie has several papers on this subject.
Article Randomised placebo-controlled trials of individualised homeo...