A newly published study offers a rare glimpse into how the opioid crisis may be affecting not only humans but also the animals they live with. According to findings published in the Journal of Addiction Medicine, over a four-year period, more than 100 household pets—mostly dogs and a few cats—were reported to have been exposed to illicit fentanyl in the United States and Canada. These exposures resulted in a wide range of concerning symptoms, such as lethargy, uncoordinated movement, and in some cases, signs of serious toxicity.
Fentanyl is a synthetic opioid that is significantly more potent than heroin or morphine. While it is sometimes used in medical settings, particularly in pain management, illicit versions have become increasingly common in the illegal drug supply. Because it is cheap to manufacture and highly potent, fentanyl is often mixed with other drugs, sometimes without the user’s knowledge. This has contributed to a dramatic increase in opioid-related poisonings and deaths across North America.
Previous studies have highlighted the risk of fentanyl exposure in children, especially when the drug is accidentally ingested in household settings. Pets, especially cats and dogs, are also frequent members of these same households and tend to explore their surroundings using their mouths and noses. This behavior puts them at risk of accidentally ingesting or inhaling small but toxic amounts of fentanyl, whether from loose powder, pills, or contaminated objects such as foil, straws, or syringes.
The research team conducted the new study to better understand how often these exposures occur in pets, what types of exposures are most common, and what signs of illness appear in affected animals. Their findings offer insight into how the ongoing drug epidemic is extending beyond human health and into the lives of domestic animals.
“Illicit fentanyl contributes to many overdoses in the United States,” said study author Orrin D. Ware, an assistant professor at the University of North Carolina at Chapel Hill. “This study highlights the potential risk of exposure to illicit fentanyl for cats and dogs, the two most common household pets in the country. To do this, we analyzed 24-hour call center data from ASPCA Poison Control to identify the most common clinical signs reported after these exposures.”
The study drew on data collected by the American Society for the Prevention of Cruelty to Animals’ Poison Control Center. This 24-hour hotline receives calls from across the United States and Canada whenever a toxic exposure is suspected in animals. Researchers looked at records from 2019 to 2023 that involved cats or dogs and had a reported exposure to illicit fentanyl. To isolate cases involving only fentanyl, they excluded any incidents involving multiple substances or prescription fentanyl intended for veterinary use.
Out of more than 600 initial reports, the researchers narrowed their analysis to 117 confirmed or suspected cases of illicit fentanyl exposure: 113 dogs and 4 cats. Most of these exposures occurred in the United States, with the highest number of cases reported in California, Washington, Arizona, and Florida. A small number of cases were recorded in Canada.
In terms of dog breeds, Chihuahuas and American Pit Bull Terriers were the most frequently involved. The average age of the dogs was under two years, and the average weight was around 10 kilograms. Most of the dogs were juveniles, which may suggest that younger pets are more likely to get into dangerous substances left within reach.
Among the dogs, the most commonly reported symptoms were lethargy, unusual vocalization, poor coordination, hypersalivation, and slow heart rate. Some cases also involved signs like hypothermia or rapid breathing. In the 85 cases where the exposure was confirmed or observed, symptoms often developed quickly after the animal had contact with the substance. For example, some dogs began showing signs within minutes of chewing on or licking an object suspected to contain fentanyl.
Cats made up a much smaller portion of the sample. Of the four reported feline exposures, two involved ingestion of suspected fentanyl pills. One cat was dropped off at a neighbor’s house in a state of immobility after being exposed in a transitional housing complex. Another cat ingested part of a suspected fentanyl tablet and showed signs such as excessive salivation. While the number of feline cases is too small to draw firm conclusions, these incidents still highlight that cats are not immune to the risks posed by unsecured opioids in their environment.
Descriptions from the poison control case notes reveal a range of exposure scenarios. Some pets were found chewing on straws or pens used to inhale fentanyl. Others ingested pills, powder, or cotton balls soaked in liquid fentanyl. In some cases, animals had access to foil or carpet that was contaminated with drug residue. One dog was reportedly exposed while lying in a bed inside a car where fentanyl had been spilled. A few incidents even involved police dogs who were exposed during drug raids.
More than half of the reported dog exposures were confirmed through clinical testing or direct observation, and most calls to the poison control center came from the pet owners themselves. The data show that illicit fentanyl can be found in many forms—powder or crystals were the most common, followed by tablets, liquid, and contaminated paraphernalia.
The findings of this case series point to a broader ripple effect of the opioid crisis. In homes where fentanyl is present—whether through active use, drug trafficking, or accidental contamination—animals can become unintended victims. Because of their small body size and the potency of fentanyl, even minute amounts can be dangerous or fatal.
“Unsecured substances and paraphernalia can pose a danger to animals, especially cats and dogs, who may come into contact with them,” Ware told PsyPost. “The most common clinical signs seen in dogs with possible exposure to illicit fentanyl include lethargy, vocalization, ataxia, and hypersalivation.”
The researchers advise that any suspected exposure to fentanyl should be treated as an emergency. Naloxone, a medication used to reverse the effects of opioid overdose, can also be effective in animals when administered promptly. Veterinarians may use intranasal or injectable forms of naloxone, and supportive treatments such as intravenous fluids may also be needed.
The study provides evidence that the dangers of illicit fentanyl are not limited to people and highlights the potential risks that unsecured opioids can pose in homes with pets. But the study has some limitations. The cases analyzed represent only those reported to a specific poison control center, which means the actual number of fentanyl exposures in pets may be significantly higher.
Some pet owners may not recognize the symptoms or may avoid reporting exposures due to concerns about legal consequences. Other incidents may go unnoticed entirely. Additionally, the study focused on fentanyl-only exposures, excluding cases involving other drugs that are sometimes found in combination with fentanyl.
More research is needed to examine how often these co-exposures occur and whether certain environments or pet owner behaviors are associated with higher risks. Future studies might also explore how pets respond to repeated low-level exposures or what long-term health effects may result from a single event.
The study, “Illicit Fentanyl Exposures in Cats and Dogs Reported to a North American Veterinary Poison Control Center From 2019 to 2023,” was authored by Orrin Ware and Brown Watts.
Ware, Orrin D. PhD, MPH, MSW; Watts Brown, Ginger DVM, DABT, DABVT
