Side Effects of CBD Oil for Dogs and How to Avoid Them

dog lying down with eyes closed
Written by Livvy Ashton | Last updated: June 21, 2023

This is a complete breakdown of the side effects of CBD oil for dogs. Here we elaborate on the most common adverse reactions to CBD products in canines, discuss CBD’s safety profile in animals, and highlight the side effects of CBD oil for dogs by the type of extract.

In case you’ve been living the life of a hermit for the past decade, CBD has become one of the most influential wellness compounds in modern history.

Cannabis compounds were banned until 2018, and CBD was the first to break the stigma and help skyrocket the popularity of other cannabinoids.

At first, researchers touted CBD oil for its ability to help humans manage a wide range of health concerns, from anxiety to depression, insomnia, pain, epilepsy, inflammation, autoimmune conditions, and neurodegenerative disorders.

But as the science dives deeper into the link between CBD and the endocannabinoid system (ECS), it turns out dogs can reap the benefits from supplementation, too.

Today, you can find a plethora of CBD pet products, including oils, treats, and topicals.

The consensus is that CBD is safe for dogs and humans, with only a few mild side effects.

In this article, we break down the safety profile of CBD oil for dogs, discuss the most common adverse reactions, and dispel all doubts you may have as a health-conscious dog parent.

Side Effects of CBD Oil for Dogs: Summary

  • CBD oil is a concentrated hemp extract containing high levels of CBD, minor cannabinoids, and terpenes.
  • CBD is a biologically appropriate compound for dogs because it modulates the performance of the ECS – the master regulatory network in all mammals.
  • Scientific analyses of CBD’s safety profile have concluded that CBD is safe for both humans and animals.
  • The most common side effects of CBD oil for dogs include dry mouth, tiredness, changes in appetite, and stomach upset.
  • Your dog may have other adverse reactions, such as low blood pressure, trembling, itchiness, or experience the side effects of CBD-drug interactions.
  • Consult your veterinarian before giving your dog CBD oil. A qualified health professional will be able to come up with the best dosage and timing for CBD and other supplements or medications.
  • Always look for relevant certificates of analysis (CoA) from a third-party lab to confirm the product’s purity and avoid the side effects of contaminated CBD oil for dogs.

What is CBD Oil?

CBD stands for cannabidiol, one of the two major active compounds in hemp and marijuana.

Marijuana is known for its intoxicating effects, but CBD alone is a non-intoxicant. It won’t get you high, and if you source it from hemp plants, the end product won’t produce psychoactive effects, either.

CBD gently interacts with the ECS to help it regulate the balance between the functions of other systems and organs in the body.

Dog parents typically give their dogs CBD oil for anxiety, fear of loud noises, pain, arthritis, mobility issues, gastrointestinal distress, and epilepsy.

CBD uses over 65 molecular pathways to reach its targets, hence the vast effects on health.

Considering its therapeutic versatility, a natural concern arises.


Is CBD Oil Safe for Dogs?

Yes, CBD oil is safe for both humans and dogs. Numerous scientific papers have analyzed its safety and efficacy, with no sign of life-threatening side effects.

The World Health Organization considers CBD “generally well-tolerated with a good safety profile.”

Organizations like the AKC Canine Health Foundation are funding studies on CBD’s safety in dogs to provide deeper insight into its benefits and side effects.

While there’s no definite answer as to its efficacy and safety in pets, PubMed doesn’t say anything about the detrimental effects of CBD in healthy dogs.

10 Side Effects of CBD Oil for Dogs

Although CBD has a decent safety profile, there are certain side effects you need to be aware of. Your dog may take too much CBD and experience adverse reactions — as with any health supplement.

Here are the 10 side effects of CBD oil for dogs to keep an eye on:

1. Dry Mouth

This is the signature side-effect of any cannabis product. Both humans and dogs can experience dry mouth after taking CBD oil because CBD affects the cannabinoid receptors in the salivary gland — inhibiting saliva production.

If CBD continuously triggers dry mouth in your dog, it can lead to poor dental health, bad breath, and discomfort during swallowing.

2. Sedation

Another common side effect of high doses of CBD oil for dogs is lethargy and sedation. Although CBD doesn’t get your dog high, it could still make them feel tired. If your dog gets sleepy after CBD, you might want to reduce the serving size.

3. Dizziness

Again, dizziness is a side effect typical of using high doses of CBD. If you notice your dog has trouble standing up, walking, and lacks proper coordination, this may indicate contamination with THC, the intoxicating substance in cannabis. That’s why we always underline the importance of third-party lab reports when you buy CBD. Only then can you confirm its purity.

4. Trembling

One of the main reasons people give CBD to dogs is to help with epileptic seizures. It’s a good compound to help with neurodegenerative disorders, such as Parkinson’s disease, too. However, at high doses, CBD has the potential to increase the tremors associated with the disease, in both humans and animals.

5. Itching

If your dog is scratching, biting, and itching a lot after taking CBD oil, it’s a sign you should reduce the dosage or withdraw the product from your dog’s routine. While this is a rare side effect, dogs can be allergic to CBD oil components. Again, you should also check the purity of your product by reading its certificate of analysis (CoA).

6. Low Blood Pressure

A temporary drop in blood pressure is a common side effect of high doses of CBD oil. This can lead to lightheadedness, which your dog won’t like. The effect on the blood pressure depends on the dose, so reducing the amount of CBD oil should help you solve this problem.

7. Stomach Discomfort

As with anything new that you introduce to your dog’s feeding routine, CBD can upset its stomach, especially if you give them in high doses. Start with the lowest dose possible and slowly work your way up to the optimal amount of CBD.

8. Nausea & Vomiting

When your dog suffers from several stomach discomfort, the body can try to get rid of it by vomiting. The bitter taste of full-spectrum CBD oil can cause your dog to throw up if they’re already not feeling well.

9. Diarrhea

CBD oil is suspended in carrier oil to improve absorption and bioavailability. Most common carriers include MCT oil and hemp seed oil. When you give your dog high doses of CBD, this can result in the overconsumption of fats and trigger diarrhea. Once you notice your dog has loose stools, it’s an indicator you should reduce the dosage, buy a more concentrated product, or switch to another form of CBD, such as CBD treats from high-quality brands.

10. CBD-Drug Interactions

CBD can inhibit a system of enzymes that breaks down the majority of pharmaceutical drugs; this system is known as Cytochrome P450 (CYP450). Taking CBD with other medications or supplements can lead to cross-interactions and side effects that aren’t typical of CBD. Depending on the type of interaction, it can cause either subtherapeutic effects or drug toxicity. Always consult your vet before you buy CBD oil for dogs to avoid these side effects.

Is CBD Safe for Dog Liver?

Some dog parents are concerned about the impact of CBD on liver health. A 2019 study found that CBD can cause liver damage in mice. However, the problem with that study is that the authors force-fed the subjects with ridiculously large amounts of CBD oil. The dose was 615 mg/kg, so if translated to dogs and humans, this amount is pointless to administer.

The study tried to make big headlines but was quickly debunked by follow-up studies and reviews that criticized its methodology and interpretation of the results.

What Are the Long-Term Side Effects of CBD Oil for Dogs?

Little is known about the long-term side effects of CBD oil for dogs. Current studies haven’t found any serious reactions. If anything, CBD can increase liver enzymes in dogs and lower blood pressure, both of which are dose-dependent.

We also don’t know the long-term psychological effects of trace amounts of THC on dogs, so you should observe your dog carefully when you give them full-spectrum CBD oils.

Different Types of CBD Oil for Dogs & Their Side Effects

Not all CBD products are the same. Dog parents can choose from three types of CBD oils for dogs:

  • Full-spectrum CBD
  • Broad-spectrum CBD
  • CBD isolate

Each type comes with different potential side effects due to the difference in their chemical composition.

Full-spectrum CBD Oil Side Effects

According to a survey of 600 dog owners about the side effects of full-spectrum CBD for dogs, these products mostly trigger dry mouth, increased appetite, and fatigue.

Here’s a more detailed breakdown of the side effect profile of full-spectrum CBD:

Side Effect Total % Minimal % Moderate % Large %
Dry mouth 47 25 20 2
Increased appetite 32 16 11 5
Sedation 30 1 10 19
Fatigue 28 17 7 4
Anxiety 21 14 5 3
Panic 15 3 7 4
Nausea 8 3 3 2
Vomiting 7 3 2 2
Impaired Cognitive Function 7 4 2 1
Dry or red eyes 5 3 1 0
Rapid Heart Rate 4 3 1 N/A
Increased Seizures 3 2 1 1

As you can see, most dogs experience dry mouth, lethargy, and increased appetite after taking full-spectrum CBD oil. This resembles the typical side effects of cannabis in humans. One theory is that the trace amounts of THC in CBD oil produce stronger effects in dogs due to their smaller size. While full-spectrum CBD oil won’t get your dog high, they can be unexpectedly relaxing and give them munchies.

According to 88.8% of pet parents, full-spectrum CBD oil was very safe. We don’t know what caused some of the side effects, such as anxiety, panic, or increased seizures. As more clinical trials are being conducted on the side effects of CBD oil for dogs, we may soon get our answers.

Broad-spectrum CBD Oil Side Effects

At the beginning of the CBD industry, the only choice was full-spectrum CBD or pure isolate.

In 2022, we saw a significant shift from these types to broad-spectrum extracts.

Broad-spectrum CBD is the middle ground between full-spectrum CBD and isolate because it doesn’t have any THC — but still offers minor cannabinoids and terpenes.

Since broad-spectrum CBD oil for dogs comes without THC, side effects like increased appetite, sedation, or feelings of unease are non-existent.

Nevertheless, your dog may experience the side effects of CBD and terpenes, including

  • Dry mouth
  • Hypersalivation
  • Loose stools
  • Vomiting
  • Dizziness
  • Increased liver enzymes
  • Allergic reactions

Isolate CBD Oil Side Effects

CBD isolate contains 99% pure cannabidiol. Its side effects are almost identical to those induced by Epidiolex, an FDA-approved antiepileptic medication:

  • Drowsiness
  • Decreased appetite
  • Diarrhea
  • Rash
  • Sleep problems
  • Increased liver enzymes
  • Feeling tired
  • Fever

Summarizing the Side Effects of CBD Oil for Dogs

The side effects of CBD oil are mild and don’t pose a threat to your dog’s life. CBD has a decent safety profile in both animals and humans.

The most common adverse reactions to CBD include dry mouth, changes in appetite, and sedation. However, depending on the type of CBD you’re giving your dog, it can also trigger diarrhea, hypersalivation, a drop in blood pressure, stomach upset, and trembling.

Giving your dog full-spectrum CBD oil may increase appetite and cause mental discomfort in high doses. These effects may be more pronounced if your dog has suffered from trauma at some point in its life.

We recommend starting with a broad-spectrum product until you introduce CBD oil with 0.3% THC. This way, your dog will benefit from the whole-plant synergy while avoiding the side effects associated with THC.


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Livvy is a registered nurse (RN) and board-certified nurse midwife (CNM) in the state of New Jersey. After giving birth to her newborn daughter, Livvy stepped down from her full-time position at the Children’s Hospital of New Jersey. This gave her the opportunity to spend more time writing articles on all topics related to pregnancy and prenatal care.