Human medicines that are dangerous for dogs and cats
Reviewed against veterinary toxicology references: October 2026
If your pet has swallowed a medicine
Call your vet or an emergency clinic now, or an animal poison control center: the ASPCA Animal Poison Control Center, (888) 426-4435, or the Pet Poison Helpline, (855) 764-7661. Both are open around the clock and may charge a consultation fee. Have the packaging, the amount and the time ready.
Short answer
Many common human medicines are dangerous to dogs and cats, sometimes in a single tablet. The most dangerous include anti-inflammatory pain relievers such as ibuprofen and naproxen, acetaminophen (especially for cats), antidepressants, ADHD medicines, baclofen, some skin creams and anything sweetened with xylitol. If your pet swallows a medicine, call your vet, an emergency clinic or an animal poison control center straight away.
The human medicines that cause the most harm
- Anti-inflammatory pain relieversIbuprofen (Advil, Motrin), naproxen (Aleve), aspirin, diclofenacStomach ulcers and bleeding, kidney failure. Naproxen lasts especially long in dogs.Most at risk: Dogs and cats
- AcetaminophenTylenol and many cold and flu productsIn cats, destroys red blood cells; a single tablet can be fatal. In dogs, liver damage.Most at risk: Cats above all
- AntidepressantsFluoxetine, sertraline, venlafaxine, duloxetine, amitriptylineAgitation, tremors, high temperature and seizures; heart rhythm problems with tricyclics. Cats are drawn to venlafaxine capsules.Most at risk: Dogs and cats
- ADHD stimulantsAdderall, Vyvanse, methylphenidateAgitation, racing heart, high temperature, tremors and seizures.Most at risk: Dogs and cats
- Sleep and anxiety medicinesZolpidem, alprazolam, clonazepam, diazepamWobbliness and sedation, or the opposite: agitation. Oral diazepam has caused liver failure in cats.Most at risk: Dogs and cats
- Heart and blood pressure medicinesMetoprolol, propranolol, amlodipine, diltiazem, verapamilDangerously slow heart rate and low blood pressure, collapse.Most at risk: Dogs and cats
- Diabetes tablets (sulfonylureas)Glipizide, glimepiride, glyburideVery low blood sugar: weakness, collapse, seizures.Most at risk: Dogs and cats
- Muscle relaxant baclofenBaclofenVomiting, wobbliness, slowed breathing, seizures and coma; small amounts can be fatal.Most at risk: Dogs above all
- DecongestantsPseudoephedrine, phenylephrine, many cold and allergy combinationsAgitation, racing heart, high temperature and seizures.Most at risk: Dogs and cats
- Opioid pain medicinesOxycodone, hydrocodone, morphineHeavy sedation, slowed breathing, low body temperature.Most at risk: Dogs and cats
- Skin and hair productsFluorouracil (5-FU) cream, calcipotriene psoriasis cream, minoxidil hair-loss solutionFluorouracil causes seizures and is often fatal to dogs; calcipotriene causes kidney failure; minoxidil causes heart failure in cats, even from licking.Most at risk: Dogs and cats; minoxidil in cats
- Xylitol-sweetened productsSugar-free gum, nicotine gum, some liquid medicines, chewable vitamins, some toothpastesSudden very low blood sugar and liver failure.Most at risk: Dogs
- Vitamin D and iron supplementsHigh-dose vitamin D, iron tabletsVitamin D causes kidney failure; iron causes vomiting and liver damage.Most at risk: Dogs and cats
- IsoniazidTuberculosis treatmentSeizures, even at low doses.Most at risk: Dogs
| Medicine | What it can cause | Most at risk |
|---|---|---|
| Anti-inflammatory pain relieversIbuprofen (Advil, Motrin), naproxen (Aleve), aspirin, diclofenac | Stomach ulcers and bleeding, kidney failure. Naproxen lasts especially long in dogs. | Dogs and cats |
| AcetaminophenTylenol and many cold and flu products | In cats, destroys red blood cells; a single tablet can be fatal. In dogs, liver damage. | Cats above all |
| AntidepressantsFluoxetine, sertraline, venlafaxine, duloxetine, amitriptyline | Agitation, tremors, high temperature and seizures; heart rhythm problems with tricyclics. Cats are drawn to venlafaxine capsules. | Dogs and cats |
| ADHD stimulantsAdderall, Vyvanse, methylphenidate | Agitation, racing heart, high temperature, tremors and seizures. | Dogs and cats |
| Sleep and anxiety medicinesZolpidem, alprazolam, clonazepam, diazepam | Wobbliness and sedation, or the opposite: agitation. Oral diazepam has caused liver failure in cats. | Dogs and cats |
| Heart and blood pressure medicinesMetoprolol, propranolol, amlodipine, diltiazem, verapamil | Dangerously slow heart rate and low blood pressure, collapse. | Dogs and cats |
| Diabetes tablets (sulfonylureas)Glipizide, glimepiride, glyburide | Very low blood sugar: weakness, collapse, seizures. | Dogs and cats |
| Muscle relaxant baclofenBaclofen | Vomiting, wobbliness, slowed breathing, seizures and coma; small amounts can be fatal. | Dogs above all |
| DecongestantsPseudoephedrine, phenylephrine, many cold and allergy combinations | Agitation, racing heart, high temperature and seizures. | Dogs and cats |
| Opioid pain medicinesOxycodone, hydrocodone, morphine | Heavy sedation, slowed breathing, low body temperature. | Dogs and cats |
| Skin and hair productsFluorouracil (5-FU) cream, calcipotriene psoriasis cream, minoxidil hair-loss solution | Fluorouracil causes seizures and is often fatal to dogs; calcipotriene causes kidney failure; minoxidil causes heart failure in cats, even from licking. | Dogs and cats; minoxidil in cats |
| Xylitol-sweetened productsSugar-free gum, nicotine gum, some liquid medicines, chewable vitamins, some toothpastes | Sudden very low blood sugar and liver failure. | Dogs |
| Vitamin D and iron supplementsHigh-dose vitamin D, iron tablets | Vitamin D causes kidney failure; iron causes vomiting and liver damage. | Dogs and cats |
| IsoniazidTuberculosis treatment | Seizures, even at low doses. | Dogs |
This list covers the most common and most serious cases, not every medicine. If your pet swallows anything not prescribed for it, call for advice.
What to do if your pet swallows a medicine
- Call your vet, an emergency clinic or a poison control center straight away, even if your pet seems fine. Some poisonings show no signs for hours.
- Have the packaging ready, with the medicine name, strength, how many tablets may be missing, the time it happened, and your pet’s weight.
- Do not make your pet vomit unless a vet tells you to. Some substances cause more harm coming back up.
- If your pet is having a seizure, struggling to breathe or has collapsed, go straight to the nearest emergency clinic.
Why pets react so differently
Dogs and cats process medicines differently from people. Cats lack some of the liver enzymes people use to clear drugs such as acetaminophen and aspirin, so even small amounts build up to toxic levels. Dogs are prone to stomach ulcers and kidney damage from anti-inflammatories at doses people tolerate. Body size matters too: a single adult tablet can be a large overdose for a small dog or cat.
Pets also find medicines in ways people do not expect. Dogs chew through pill bottles and eat tablets dropped on the floor, flavored chewables and gummies attract them, and cats lick creams and solutions from their owners’ skin or from their own fur.
When a human medicine is prescribed for your pet
Many medicines vets prescribe are human drugs, such as gabapentin, trazodone and fluoxetine, and they are safe at the dose and form the vet chooses for your pet. The danger comes from giving a pet a medicine prescribed for a person, guessing a dose, or using a formulation with an ingredient such as xylitol. If your pet needs a human medicine, have your vet prescribe it; see which pet medicines a regular pharmacy can fill.
Keeping medicines away from pets
- Keep pills, pill organizers and bags or purses that hold medicines in a closed cupboard, not on counters or nightstands.
- Take medicines where a dropped tablet can be found quickly, and look for any you drop.
- Store pet and human medicines separately, so a pet never gets a person’s medicine by mistake, or the reverse.
- After applying a cream, gel or hair solution, wash your hands and keep pets from licking the area until it is dry or covered.
- Dispose of medicines you no longer need through a take-back program rather than the trash.
Frequently asked questions
Can I give my dog ibuprofen or naproxen?
No. Both can cause stomach ulcers and kidney failure in dogs, even at doses that are safe for people. Vets prescribe anti-inflammatories made and dosed for dogs instead.
Can I give my dog or cat Tylenol?
Never give acetaminophen to a cat: it destroys red blood cells and can be fatal. Do not give it to a dog unless your vet has prescribed a specific dose.
Can I give my dog Benadryl?
Only on your vet’s advice and dose. Some vets use diphenhydramine for dogs, but combination products with decongestants, and liquids sweetened with xylitol, are dangerous.
What are the signs my pet has swallowed something dangerous?
Vomiting, drooling, wobbliness, tremors, seizures, unusual sleepiness or agitation, a racing heart, breathing trouble, pale gums or collapse. Some poisonings show no signs for hours, so call even if your pet seems well.
How much medicine is dangerous?
It depends on the medicine and your pet’s size, and for some medicines one tablet is enough. Do not wait to see; call your vet or a poison control center with the packaging in hand.
Should I make my pet vomit?
Only if a vet or poison control center tells you to. Some substances cause more harm coming back up, and home methods can be dangerous.