WLP getting tested for Inclusion body disease.

[Bogertophis]

Just to be on the safe side, I'd wait a good 5 days to make sure he keeps this one down before visiting the vet again- & I agree w/ bcr229 also.

To the best of my knowledge, Flagyl (metronidazole) doesn't treat for hookworms- but yes, it tends to stimulate a snake's appetite, as it gets rid of protazoans. (not hookworms) If your snake was only given Flagyl, it's likely that the hookworms are still alive & well. BTW, metronidazole is also sold for dosing tropical fish. ("Aqua-Zole" or "Fish-Zole" etc)

It's been a while since I've needed either one, but to get rid of worms in a snake, I've used fenbendazole (Panacur), in the form of horse dewormer paste* (put in the oral cavity of the mouse that was fed). For safety, I cautiously used a somewhat lower dose & repeated it several times, so as not to cause a massive die-off of worms that can (in some cases) die off & cause blockages** in areas they may have migrated to in a snake's body. (**which could also cause other & sometimes serious, even fatal issues). Remember, "First do no harm".

*(https://www.chewy.com/panacur-equine...gaApT2EALw_wcB

To the best of my knowledge, Ivermectin is more effective against hookworms, but it's also pretty strong & can harm (kill) a snake if not used VERY carefully. It too is sold in various forms- a paste for deworming horses, & an injectable form for cattle. I actually use the latter (a TINY calculated dose extracted from the bottle with a syringe) every month to prevent heartworm in my dogs- years back, my then-vet told me about it, as it's so much less expensive than the oral chewies sold for dogs, but it's not the best method for everyone. The tiny dose is then applied to something the dog eats- I use a bit of bread w/ peanut butter to cover the medicinal taste. My dogs have never had heartworms & I've been safely using this for years. But always ask your vet before using this for your dogs- as there are some dog breeds that are sensitive to all these medications, & this one has very little margin for error- and especially in snakes! Ivermectin is sold in feed stores without prescription, fyi. And I've NEVER used it on a snake, btw.