I’ve worked many overnight shifts on Halloween. (I didn’t last year, and my pal Buster was very excited that I wouldn’t be dressing him in a costume.) Many people have asked me about the looming menace that Halloween poses to dogs and their health and safety. It’s true that Halloween brings many potential canine dangers, but I’m happy to report that with only one exception, most Halloween-related problems are rare.

Just the same, here are some of the things that can go wrong with your dog on Halloween, starting with the only really common one:

1. Candy

Halloween marks the official start of canine chocolate toxicity season, which runs through the holidays and ends on Jan. 2.

Lots of candy being hoarded by lots of careless kids is a recipe for massive chocolate ingestion in dogs. Chocolate contains two related canine toxins. One, caffeine, is well-known to everyone. The other, theobromine, is what causes a chocolate “high” in people. In dogs, it can cause agitation, gastrointestinal upset, tremors, seizures, heart palpitations, and death.

Different types of chocolates pose different risks. In general, the darker the chocolate, the greater the potential toxicity. Baker’s chocolate (which isn’t commonly distributed on Halloween) is really dangerous stuff. Those 72 percent cacao chocolate bars that are all the rage are pretty bad as well. Snickers and Milky Way bars contain hardly any theobromine.

However, if a child (of any age) leaves an entire goody bag unattended within reach of the family dog, there is the potential for a lethal overdose. The nougat in milk chocolate treats can also cause gastrointestinal upset or even pancreatitis.

Sad to say, it’s not just chocolate that poses a menace in Halloween bags. You know those goody two-shoes who give out boxes of raisins? Not only are these killjoys asking for their houses to be egged by angry kids, but they might also be dog killers. Raisins have the potential to cause kidney failure and death in dogs.

Recently, a new threat has also emerged in the goody bag: xylitol. Xylitol is an artificial sweetener that is used in most sugar-free gums and many sugar-free candies. It’s super dangerous for dogs — xylitol has the potential to cause fatally low blood sugar. It also can cause liver failure.

The moral of the story is clear and simple: Keep Halloween goody bags out of dogs’ reach. And please, for the love of all things decent, don’t give out raisins to trick-or-treaters.

2. Costumes

I’m referring to human costumes here (there will be more on canine costumes below). Novel fabrics, especially if they are coated with candy or food debris, can be attractive to dogs. Silly dogs might consume all or portions of costumes, leading to intestinal blockage, which can be fatal without surgery or an endoscopy.

3. Kids walking dogs at night

Some kids like to take their dogs trick-or-treating. It’s a bad idea. Small children often have trouble controlling dogs, and on wild nights such as Halloween dogs are more likely to be startled and to escape from someone who’s not big enough to really have control. If your dog must go trick-or-treating, an adult should hold the leash and the dog should be fitted with a light on his collar.

4. Drunks and party people

Speaking of wild nights, Halloween is one of the biggest drinking holidays of the year. Drunken people behave erratically and can upset dogs. They also might find it funny to feed chocolate or raisins to pets. Your dog will be better off away from the drinking and partying.

5. Fireworks

Another thing that drunk people enjoy is lighting fireworks. There aren’t many universals in this world, but I think it’s safe to say that no dog likes fireworks. Lately I’ve been hearing lots of firecrackers and bottle rockets on Halloween, so I recommend keeping your dog inside and away from the action.

What’s not a risk for dogs?

I am happy to announce two things people believe are risks for dogs but really aren’t, in my experience.

Degrading dog costumes

Although poorly designed costumes might pose strangulation risks, there is no such thing as a costume that will cause emotional scarring in your dog. Any creature that will gladly lick his nether regions in public is not capable of feeling degraded by even the silliest of costumes.

Rectal firecrackers

When I was growing up in Idaho, we kids took it as truth that any pet left outside on Halloween night would be caught by Satanists who would then put a lit firecracker up his butt. I’m happy to say that the whole Satanist scare of the ’80s was an urban legend, and that I’ve never treated a rectal-firecracker injury in a pet.

In short, although Halloween poses some risk to your dog, it’s not too hard to stay safe. Keep your dog inside and away from the candy and he’ll most likely make it through the night unscathed.

Read more about dog safety and Halloween:

• How to Win a Dog Halloween Costume Contest
• 7 Tips for Keeping Your Dog Safe on Halloween
• 3 Ways Dog Halloween Costumes Can Cross the Line
• Guess What These Dogs Are Dressed as for Halloween?
• Stop Procrastinating and Get Your Dog’s Halloween Costume!

Got a question for Dr. Barchas? Ask our vet in the comments below and you might be featured in an upcoming column. (Note that if you have an emergency situation, please see your own vet immediately!)