Karen, Melatonin is a hormone. It's supposed to help you sleep. It is naturally produced by your body, but supposedly the amount decreases as you age. I have tried it twice. It did help me to sleep. After the first night of taking it, I had a moderate allergy attack the following day. After the second night, I had a severe allergy attack (constant sneezing) the next day despite the fact I take Claritin D every day. That was the last time I will ever take that stuff. After doing a search on the internet, I found that people with immune disorders and allergies should not take it (there was no warning on the product I took). Apparently, melatonin gives the immune system a boost. Hence, my allergy attacks. Please be careful if you choose to use this stuff. If your ferrets have an undiagnosed immune system problem, you could be making it much worse. Suzanna [Posted in FML issue 3155]