Medically Reviewed by
Jason Crawford

Article Last Updated on January 10, 2023

Imagine this situation – you’re a person who often travels with a stash of CBD oil, a dab pen, or an edible in your luggage as a part of your medical marijuana treatment, and a police officer along with a dog approaches you at the airport. Your first thought is probably wondering whether the dog could smell the cannabis inside your vaporiser. The short answer to this question is yes, sniffer dogs can smell the weed inside your vaporiser.

It’s no news that a dog’s nose has a better developed sense of smell compared to a human nose. That’s the reason why law enforcement trains these animals to become sniffing dogs that can detect anything from illicit drugs to guns, machinery, explosives, even missing people. Today, drug-sniffing dogs trained to pick up specific scents can be seen at airports, traffic stops, and public events accompanied by police officers.

So, let’s go into how these animals detect drugs using their highly developed sense of smell, the most common breeds that do this, and what exactly they can detect.

Can All Dogs Be Trained to Become Drug Sniffer Dogs?

While regular dogs have a developed sense of smell, they couldn’t recognize all the different substances that drug sniffer dogs can. In order to become sniffing dogs, dogs first need to be trained. That’s done by professional dog trainers who use the 300 million olfactory receptors located in the dog’s nose to train them to sniff out the desired substance. Afterward, the Transportation Security Administration (TSA) uses these dogs to search for illicit substances.

About Drug-Sniffing Dogs

Before we go into the whole subject about K-9 dogs detecting weed, we need to get into the background of the animals that are being used to sniff out drugs. Dogs generally have about 10,000 times more olfactory receptors for smell located in their nose compared to humans. But even so, not all dogs are chosen for this job. Some dog breeds are preferable when it comes to training them as sniffing dogs.

The breed that’s mostly associated with this service is the German Shepherd breed, that has around 225 million scent receptors, although other pure-breed and mixed-breed dogs can be trained to recognize specific scents. The most common are:

  • Beagles;
  • Basset Hounds;
  • Bloodhounds;
  • Weimaraners;
  • Labrador retrievers;
  • Golden retrievers;
  • Belgian Malinois. 

After choosing the breed, the next step is training the dog to be a drug-sniffing dog.

How Police Dogs and Customs Dogs Are Trained to Detect Illicit Substances

The dogs that go into training to become detection dogs have a very specialized training alongside their human partners. Generally, a dog can be trained to detect anywhere from 2 to 5 different substances.

After being selected, the dogs train extensively for a couple of months and go through daily routines until they’re ready for fieldwork. The dog is trained to associate their favorite toy with the smell of the desired substance that it needs to learn how to detect. For example, the scent is sometimes put on a towel and the trainer plays tug of war with the dog. After the dog detects the smell, it can:

  • Growl;
  • Stare;
  • Alert the police officer;
  • Bark;
  • Whine;
  • Raise its paw;
  • Raise its ears;
  • Jump up;
  • Dig;
  • Touch the nose to the location where it detects the smell.

After the dog detects the smell and does one of the above-mentioned things, a treat is offered as a reward. That way the police dog can learn to associate the smell of the substance with playtime, and expect a treat at the end.

Can Drug-Sniffing Dogs Smell Weed Cartridges?

Sniffer dogs are trained to smell the THC found in weed. Moreover, they can also be trained to smell specific terpenes found in cannabis like pinene, caryophyllene, and beta-caryophyllene. So, yes, drug-sniffing dogs can be trained to smell the weed in cartridges found in vape pens. Even CBD oil can be detected by detection dogs if they’re trained to sniff it out.

What Else Can K-9 Dogs Detect?

As marijuana use is legalized in a lot of states, and pending legalization in others, police officers are shifting the focus from marijuana to the detection of other drugs like:

  • Cocaine;
  • Heroin;
  • Methamphetamine;
  • Opium;
  • MDMA.

Apart from drugs, detection dogs are also used to search for:

  • Firearms;
  • Explosives;
  • Missing people;
  • Fire accelerants;
  • Mobile phones;
  • SIM cards and USB drives.


If you’re used to vaping, you should know that the K-9 unit’s detection dogs can sniff the weed in your vape pen if they’re around you at an airport or a festival. Depending on which substance the dog is trained to sniff out, it can sniff out anything from vape cartridges to edibles, CBD oil, and other marijuana products

As marijuana legalization is increasing around the world, more and more sniffing dogs are trained to sniff out other illicit drugs like cocaine, heroin, meth, opium, and MDMA, as well as firearms and bombs. 

A passionate advocate for the benefits of cannabis. Fraser Horton, who has a background in botany and a strong love of nature, has spent years researching how cannabis affects the body and mind. He established Leaf Nation in 2020, where he has devoted himself to educating people about the legalisation of marijuana and its safe and responsible use. Fraser is committed to highlighting cannabis’ potential for improving wellness and working to dispel the stigma associated with its use.


The information presented on this page is provided as a public service to aid in education and is derived from sources believed to be reliable. Readers are responsible for making their own assessment of the topics discussed here. In no event shall Leaf Nation be held reliable for any injury, loss or damage that could happen if using or abusing drugs.