Will NyQuil Kill A Dog?


Human medications are definitely not for pets.

But what happens when your dog accidentally ingests some of your flu meds?

Will they get seriously sick, or will your dog be fine?

Or maybe you’re looking for a good sedative to calm your dog’s anxious nerves.

And you’re wondering if NyQuil is safe?

Or will it kill your dog?

Okay, let’s be real!

NyQuil is safe for humans but toxic to dogs, and it can be lethal if they ingest a large amount of it.

Really, NyQuil and many other human medications have no business being in your dog’s body. 

What is the active ingredient in NyQuil?

NyQuil is an over-the-counter medication commonly used for treating flu, cold, allergies and flu-like illnesses.

NyQuil helps to relieve sore throat, runny nose, coughing, headaches, sneezing, fever and other symptoms of common cold.

This medication provides great relief for flu patients,  and it also helps them sleep comfortably through the night. 

The active ingredients in NyQuil are: doxylamine, acetaminophen, and dextromethorphan (DXM). Doxylamine is an anti-allergy medication which soothes sore throat, nasal congestion and sneezing.

Doxylamine also causes drowsiness, which helps patients to fall asleep.

Acetaminophen alleviates fever and pain, while dextromethorphan reduces coughing. 

Can a dog take NyQuil?

You should never give your dog NyQuil or any human medication for any reason.

If your dog is sick with the flu, it’s safer to get them to the vet for a prescription.

NyQuil is not safe for dogs and should never be given to them, whether intentionally or accidentally.

The active ingredients in NyQuil are not safe for dogs, especially acetaminophen.

Here is how doxylamine, DXM and acetaminophen affect dogs:

Doxylamine: Dogs are frequently prescribed doxylamine succinate to treat allergies and itching. It’s an antihistamine, which is why it’s used in cold medicines for humans. When prescribing doxylamine for dogs, the recommended dosage is ½ to 1 mg per pound of body weight. The dosage in NyQuil is about 12.5 mg of doxylamine for 2 capsules or 2 tablespoons. Most dogs will probably not be harmed by this dosage.

Dextromethorphan: (or DXM) is also sometimes administered to dogs. It’s not usually given to dogs for cough, but used to treat compulsive behavior instead. The recommended dosage for dogs is 1 milligram per pound of body weight. However, NyQuil contains about 10 to 15 mg of DXM in each capsule or each tablespoon, and a single dose of 2 capsules is enough to poison a small dog.

DXM poisoning is more common in puppies and small dog breeds. Large dog breeds, on the other hand, can become ill if they take too much. An overdose of DXM can trigger a variety of symptoms in dogs. The most common symptoms of DXM poisoning include fever, tremors, anxiety, etc. 

Acetaminophen: this is a good painkiller for humans, but it’s harmful to dogs. Dogs can have a swollen face, vomit, lose appetite, and have discolored gums as a result of ingesting acetaminophen. This medication can also cause liver damage in dogs. OTC pain relievers (containing acetaminophen) can be particularly toxic and even lethal to dogs. Theraflu, DayQuil, NyQuil, and Tylenol all contain acetaminophen and should never be given to dogs. 

What happens if your dog eats NyQuil?

Despite how toxic acetaminophen is to our pets, this type of toxicity is unfortunately still common. This is often due to dogs getting into their owner’s medicine cabinet and ingesting drugs. But sometimes, it can be that a pet owner attempted to manage their dog’s pain at home and unfortunately administered the wrong drug.

Acetaminophen has a very little safety margin in dogs. The safety margin of a drug is the difference between the usual effective dose and the dose that causes severe or life-threatening side effects. When a dog takes a toxic dose of acetaminophen, they become very weak and unable to walk. You may notice your dog drooling, vomiting, and panting with a rapid heart rate. They will also have discolored gum and eye globes. You may also notice some swelling on the face, paws and limbs. 

Acetaminophen also affects the ability of red-blood cells to effectively transport oxygen. In severe cases of poisoning, there will be liver damage with symptoms like dark urine, discolored feces, swollen stomach, skin discoloration and yellow eyes. The situation can be fatal if these symptoms are not quickly recognized and the dog is not given proper treatment.

How Much Acetaminophen is Toxic to Dogs?

Acetaminophen has a poisonous dosage of 75-100 mg per kilogram of body weight in dogs. Toxicity would be reached at 450 mg in a 10 pound dog. The dosage of acetaminophen in Tylenol capsules ranges from 325 mg to 650 mg per capsule. And 325 milligrams of acetaminophen is contained in one spoonful of NyQuil or one NyQuil capsule. Your dog is unlikely to be poisoned by one capsule. However, your dog may get sick if they swallow a significant number of painkiller pills or a large amount of NyQuil.

Is there any treatment for Acetaminophen toxicity in dogs?

Preventing acetaminophen toxicity is the best way to deal with it. Ensure that you keep all your medication in a locked cabinet, where your pets will be unable to reach them. Also, never try to treat your dog’s illness with human medications. Ibuprofen (Advil), acetaminophen (Tylenol), aspirin, or any other pain medicine meant for human use should only be given to dogs under the supervision of a veterinarian.

But if your dog already has acetaminophen in their system, the best way to deal with that is prompt treatment and decontamination. If you noticed the ingestion as soon as it occurred, there is a chance of preventing poisoning if you can get to the vet very quickly. The vet will induce vomiting to purge the system of the toxin. After the controlled vomiting, activated charcoal may also be used to get rid of any remaining traces of the toxin from your dog’s system and further reduce the chances of toxicity. This should only be done by a vet. 

Your dog may be hospitalized depending on the amount of acetaminophen they ingested. If it’s a very large dose, then they may be given N-acetylcysteine, an antidote for acetaminophen poisoning.

The treatment for acetaminophen toxicity is more intensive in very severe cases. For instance, a dog will need vitamin K or plasma transfusion if there has been damage to the liver. 

How to prevent NyQuil poisoning in dogs?

There are two ways to prevent your dog from getting poisoned with NyQuil. The first and more obvious one is to never give NyQuil or any other human medication. Self-diagnosing and self-medicating your dog can be very dangerous because you may end up giving a medication that is harmful or even the wrong dose of the right medication. Always let the vet treat your dog. 

And the second way to prevent NyQuil poisoning is to store your medications in a place your dogs and kids can’t reach. Accidental ingestion of the wrong medication has caused many medical emergencies for pet parents, and you can prevent this if you ensure that you don’t leave your meds carelessly lying around. 

What other medications contain Acetaminophen?

Besides NyQuil, DayQuil and Tylenol, there are many other medications that contain acetaminophen. Here are some other medications that contain acetaminophen:

  • Excedrin
  • Alka-Seltzer Plus
  • Mucinex
  • Robitussin
  • Goody’s
  • Panadol
  • Theraflu

You can’t possibly know all the medications that are potentially toxic to dogs, therefore it’s safer to treat all medications as potentially toxic and keep them safely locked away. 

What can I give my dog to calm anxiety?

Dogs experience anxiety, and sedatives can help them calm down and relax. But, human sedatives should not be given to dogs. There are sedatives that are specially made for dogs. 

The most widely given oral sedative for dogs is acepromazine. It works by inhibiting dopamine receptors in the brain, and suppressing some brain activities. The liquid form of acepromazine is more effective than the tablet. This medication should only be given under the supervision of a veterinarian due to certain side effects like low-blood pressure. If your dog has anxiety or flu, talk to your vet. Your dog’s vet is in the best capacity to prescribe the most appropriate sedative for your dog. And whichever medication is prescribed, ensure that you follow the exact dosage prescribed. 


NyQuil is a very effective flu medication, it relieves flu symptoms and helps patients sleep well at night. However, NyQuil is a human medication and not for dogs, it has no business in your dog’s system. NyQuil is toxic to dogs because it contains some ingredients that are harmful to dogs. The ingredient in this flu medication that makes it most toxic to dogs is acetaminophen. 

If your dog accidentally ingested NyQuil or any acetaminophen-containing med, they need immediate veterinary attention. The vet will induce vomiting, administer activated charcoal or acetaminophen antidote, depending on the severity of the case. If your dog is sick with the flu, or you need to give them a sedative, ask your vet for a prescription. Never try to self-medicate your dog to prevent an unfortunate case of toxicity, and keep all medicine locked up and away from your pets. 

Photo credits

¹ Photo by Steven Schwartz on Flickr

James Grayston

My name is James and I love dogs. have owned four Golden Retrievers in the past 15 years. Currently I own two "Goldies"- a five year old and a seven month old. The photo shows me with our youngest when she was about 7 weeks old!