Check out the website for diclectin.
What is diclectin?
Long story made short... Diclectin is the same thing as Bendectin, which was produced in the United States until 1983 when it was voluntarily removed from the market following lawsuits alleging birth defects. You can find out more about the history of this drug here.
What is it? It's very simple - from the website, it's:
"a combination of 10 mg of doxylamine succinate and 10 mg of pyridoxine hydrochloride (vitamin B6) in a delayed-released formulation"
The FDA's subsequent testing revealed no teratogenic effects, and the overall conclusion is that Bendectin is probably perfectly safe. However, it still is not produced in the United States - only in Canada under the name Diclectin (Canada = Diclectin, US = Bendectin, UK = Debendox).
Thankfully, it's easy to remedy - mothers can simply combine 10 mg of vitamin B6 and 10 mg of Unisom to get the same thing (although it's not time-released). Many women do, and I would have no problem doing so.
This works for some women and doesn't work for some. It's basically a line of first defense - something to try before heading for the big guns.
Check out the website. It's extremely biased toward Diclectin (I wonder why!), but you can get some basic information off of it.
* The usual disclaimer: I am not a doctor, and the above is not medical advice. You are fully responsible for any medical decisions you take regarding supplements, and all decisions should be discussed with your midwife, OB, or physician.