I'm not sure what they put in the remedies but I would like to know if they are kosher and would batel beshishim apply in this case if there was a non-kosher ingredient?
Some Halachic sources relating to homeopathy:
1) Hamaor (journal) Sh'vat 1983. Someone asked R' Moshe Feinstein concerning the kashrut of homeopathic 'remedies' on Passover. (Would the prohibition against purposely nullifying a substance apply?) The response came from Rabbi Moshe Tendler who wrote that his father-in-law didn't want to deal with the question because homeopathy is nonsense:
I emphasized the terms tested and confirmed (בדוקה ומנוסה) because they refer to the prohibition against superstitions- "darchei haemori". The source in Shulchan Aruch is OC:301. Basically, any cure that has no basis in science and has been proven ineffective (or perhaps not proven effective) is forbidden as a superstition. (There are nuances that need further study.) Indeed, homeopathy has been proven ineffective (see wikipedia for references to the meta-studies) and has no rational basis in science. (I can speculate as to the meaning of the rest of the letter. Many people who believe and promote homeopathy tend to have other strange beliefs. There is a definite connection between homeopathy and the occult/superstitions. Major influential homeopaths such J. T. Kent, Edward Bach and George Vithoulkas were/are occultists. More than half of Wikipedia's list of homeopaths have some connection to the occult/spiritualism/new age. In some cases, outright idolatry is involved.)
The article in the HaMaor journal continues with two rather strange responses to Rabbi Tendler/Feinstein's "non-responsum". They include halachic non-sequitors, a bizarre claim that homeopathy is respected by doctors/scientists, an accusation that Rabbi Tendler fabricated his father-in-law's response, and even an ad hominem attack against Rabbi Tendler for attending university.
I found three other reponsa that deal with Rabbi Feinstein's negation of homeopathy:
1) Rabbi Chaim Dovid HaLevi in T'chumin, Volume 3. He deals with the Passover issue and the question of non-scientific (segulot) remedies in general. (I would humbly suggest anyone reading the responsum to study all the sources he cites very carefully. Especially problematic is that he disregards the major point that Rabbi Tendler makes- that homeopathy is not בדוקה ומנוסה ; instead he only deals with the issue that homeopathy has no scientific explanation.)
2) R' Menashe Klein, Mishneh Halachos, Vol. 10, 112. (He doesn't understand why homeopathy would be considered nonsense/non-scientific. He doesn't deal with the issue of בדוקה ומנוסה)
3) R Wosner, Shevet HaLevi, Vol. 5, 55. (He seems to conclude that the remedy is permitted if it has been established as effective and accepted by medical experts.)
Wikipedia includes this sentence in its article on homeopathy:
If there is not a single molecule of a non-kosher ingerdient, what possible problem can there be?
This link lays out all the relevant points is for using homeopathic medicines