I had to use the Starlight Bloodhound stuff this year and it DOES work. You need complete darkness to see it glow, though, so it works better if you bring flashlights with you instead of a lantern. The only complaint I have about the Starlight Bloodhound is that it also lit up the moss that grows in our woods, too, so we had lots of false positives until we realized what was going on. Once we started spraying it only on the leaves, we were able to establish the line the deer had travelled and found it quickly.

I wanted to buy a Carnivore, but the store was sold out. Being desperate (it was raining and dark and I had a deer down in the woods), we grabbed the next best thing we could find.