Most pet owners have heard they should keep dogs away from chocolate and cats away from lilies. But did you know that just a few sticks of sugar-free gum could cause liver failure in your dog? Or that half a tablet of Tylenol could put your cat into a coma?

Pet poisonings are common and have been happening more often in recent years, says Tina Wismer, D.V.M., medical director of the American Society for the Prevention of Cruelty to Animals Animal Poison Control Center. This month, the ASPCA released data showing that its hotline handled 180,639 such cases in 2016. 

We've compiled a list of the most common pet toxins reported to the ASPCA in 2016 and what you can do to prevent a poisoning from happening in your home. (Unless otherwise noted, these are applicable to cats and dogs.) 

Most of these medications, foods, and chemicals aren't safe in any amount for pets, but the severity of a reaction depends largely on the animal's size. “It’s going to take a lot less for a chihuahua than it is for a Great Dane to cause a problem,” Wismer says.

If you think your pet has been poisoned, take the food or chemical away and immediately call your vet. If you can’t get through, try the ASPCA Animal Poison Control Center (888-426-4435). (The ASPCA might charge a $65 consultation fee.) 

1. Medication

Prescription and over-the-counter drugs intended for humans were the two most common sources of pet poisoning in 2016.

ADHD drugs, antidepressants, and heart medications top the charts because they’re some of the most commonly prescribed, Wismer says, and pets can end up accidentally ingesting them if they spill out of a bottle or aren't properly stored. There are additional risks in households with children. Sometimes children feed their own meds to their pets intentionally, Wismer says, or they leave a medication that's been hidden in food on their plate and their pet eats what's on the plate.

Other frequent poisoning sources include thyroid medication and over-the-counter drugs such as acetaminophen (Tylenol), ibuprofen (Advil), and naproxen (Aleve).

Veterinary drugs for your pet, such as nonsteroidal anti-inflammatory medications (NSAIDS, like aspirin) and phenylpropanolamine tablets (used to treat urinary incontinence), are also a common cause of pet poisonings. They’re safe when used as prescribed, but because they often come in tasty flavors, your pup might gobble up too many if they're left within reach.

When you call your vet, it's helpful to know the strength of the medication swallowed, about how much your pet ate, and whether it ate any of the packaging, which could potentially change the treatment or cause an internal obstruction.

Common Symptoms If Your Pet Ingests . . .

  • ADHD drugs: Agitation, elevated heart rate and blood pressure, and if taken in large doses, seizures.
  • Antidepressants: Agitation, panting, rapid heart rate, vomiting, drooling, diarrhea, seizures.
  • Heart medication: Lower blood pressure and eventually heart failure. Symptoms include depression, not eating, vomiting, diarrhea, and seizures.
  • Human thyroid meds: Muscle tremors, nervousness, panting, rapid heart rate, and aggression.

  • Ibuprofen (Advil), naproxen (Aleve), and NSAIDS: Stomach ulcers and kidney failure, which may include vomiting, bloody stool, and a lack of appetite.

  • Acetaminophen (Tylenol): Panting, gum color changes, vomiting, and weakness, which can ultimately end with irreversible liver damage. Initial symptoms can occur within 24 hours after ingestion and maybe after only one or two Tylenol tablets taken, depending on the size of your pet.

  • Phenylpropanolamine: Abnormal heart rate, agitation, dilated pupils, high blood pressure, tremors, and seizures.

Prevention Tips

Take your meds over the sink or in a room with the door closed, and store them where your pets can’t get to them. Don’t keep pills in your pocket or on a counter, and keep them separate from other strong-smelling pills such as fish-oil supplements (which aren't harmful to pets but might attract your hungry pet to your pill stash). Watch children closely when they take medication to ensure they don’t drop it or decide to feed it to Fido. Ask your vet if unflavored medications are available for your pet.

2. Food

Chocolate, unsurprisingly, causes more pet poisonings than any other food. Such poisonings have actually become more severe as our tastes have shifted to darker chocolates, which are more toxic to dogs than milk chocolate, says Wismer. It would take about 9 ounces of milk chocolate, 4.5 ounces of dark chocolate, and just 1.5 ounces of super-dark Baker’s chocolate to cause a seizure in a 20-pound dog, according to Wismer.

Xylitol is the next most common source of food-related pet poisonings. Manufacturers add this low-calorie sugar substitute to processed foods and other products such as baked goods, breath mints, gum, mouthwash, toothpaste, and even some types of peanut butter. (Check the ingredients list to be safe.)

Grapes and raisins can be toxic to dogs' kidneys, and onions and garlic can cause red blood cell damage in pets. It's helpful to know roughly how much was eaten before you call your vet.

Cats are sensitive to many of these foods, too, Wismer says, but they're less likely to dip in because they’re pickier eaters and have less of a sweet tooth than dogs. “A cat may nibble on a brownie,” she says, “but a dog will eat the entire pan.” 

Common Symptoms If Your Pet Ingests . . .

  • Chocolate: Agitation, quickened heart rate, vomiting, diarrhea, and seizures.

  • Xylitol: Rapid spike in insulin levels, which could cause your dog’s blood sugar to plummet to dangerous lows.

  • Grapes, raisins, and currants: Vomiting and kidney failure (in dogs only).

  • Onions, garlic, and chives: Disorientation, fatigue, listlessness, pale gums, and rapid heartbeat can progress to darkened urine, jaundice, and vomiting.

Prevention Tips

Keep your pets away from the kitchen when cooking. Contain your trash with a tightly-sealed lid or inside a cupboard that’s hard to open. If you stash gum, breath mints, or candies flavored with xylitol in your purse or backpack, don’t leave it lying around where your pet can get into it. 

3. Cleaners and Other Household Supplies

Household cleaners such as drain openers, oven cleaners, and disinfectants are the most common poisons in this category. Depending on the concentration, they can cause chemical burns on the paws or in the mouth or stomach. Animals also love to get into paint, but generally that causes only an upset stomach.

Wismer says the ASPCA also gets many calls about batteries, typically after dogs bite into a TV remote. “If they puncture and open the batteries, they can potentially cause burns in the mouth,” she says. 

If your pet gets splashed with paint, don’t clean it off with a paint thinner or other chemical solvents because they can cause chemical burns. Try a bath with soap and warm water instead, or trim that section of fur. If you know your pet has taken a lick of a corrosive cleaner or a bite into a battery, a little milk or water can help dilute it, Wismer says—but you should still call your vet for advice on what to do next.

Common Symptoms If Your Pet Ingests . . .

  • Household cleaners and batteries: Drooling, vomiting, rubbing at the mouth, and not wanting to eat. Cats may also develop a swollen or protruding tongue.

Prevention Tips

Lock pets in another room while you’re cleaning, and don’t let them back in until you’re done and the liquid has evaporated, Wismer advises. Store all of your cleaners, as well as batteries or any electronics that house them, in a place your pet can’t reach. If storing them under the sink, a baby lock can help keep them out. Clean your remote regularly to keep tasty crumbs and food scents off.

4. Pesticides and Rat Poison

Certain insecticides that contain active ingredients like carbamates, organophosphates, pyrethroids, pyrethrins, and permethrins, which some people spray on their lawns, can be toxic to cats and dogs as well as to bugs. And make sure to read the label on flea and tick medications before applying them to your pet. Some are fine for dogs but toxic to cats.

Dogs also tend to find slug and snail baits that contain metaldehyde—as well as rodenticides (which are grain-based)— tasty, but it can make them very sick. Cats aren’t usually attracted to rodenticides, but if they eat a mouse or rat that has been poisoned by the bait, they could end up being poisoned themselves. The same goes for dogs.

Each type of rat poison works differently in the body, so treatment after a poisoning will differ. Keep the box after placing rodenticides around the house, Wismer says, so you have the details on hand when you call your vet.

Common Symptoms If Your Pet Ingests . . .

  • Insecticides containing organophosphates, carbamates, pyrethroids, pyrethrins, and permethrins:Vomiting, diarrhea, tremors, convulsions, paralysis, respiratory failure. (These symptoms can occur in cats and dogs, but cats are much more sensitive.)

  • Snail and slug baits with metaldehyde: Tremors, seizures, an abnormal gait, and a rapid heart beat.

  • Anticoagulant rodenticides: Weakness, difficulty breathing, and pale gums. (Symptoms typically appear after about three to seven days.)

  • Bromethalin-based rodenticides: Brain swelling, seizures, and paralysis in the hind end. (Symptoms typically appear within 8 to 12 hours. This type of poisoning is often fatal, Wismer says.)

Prevention Tips

If you must apply an insecticide to your lawn or garden, look for nontoxic alternatives such as those with the active ingredient Bacillus thuringiensis (or “Bt”), and dilute them properly before applying. If you're using an insecticide that might be toxic, apply it only to areas your pets can’t reach.

Avoid slug and snail baits that contain metaldehyde, and place them in parts of the garden that your pet can’t get to. Do the same with rodenticides.

5. Plants

Lilies were the most common source of plant poisonings in 2016, Wismer says. They’re extremely toxic to cats; even just a tiny nibble of a leaf or flower, or a lick of some pollen that has fallen on a cat's fur could cause severe kidney failure. Dogs, however, aren’t affected.

Cycad palms, which are abundant in warm states like California, Florida, and Texas, are also extremely toxic to cats and dogs. And some common houseplants—including dieffenbachia, peace lily, and philodendron—contain compounds called insoluble calcium oxylates, which can be extremely harmful when eaten. If your pet bites into these plants, they can release needlelike crystals that can shoot into their gums or tongue. If they eat enough, which is rare, Wismer says, their mouth can swell so much that they can’t breathe. 

The ASPCA provides a list of plants that are poisonous to pets, with a photo of each.

Common Symptoms If Your Pet Ingests . . .

  • Lilies: Vomiting, lethargy, decreased urine output, and kidney failure (in cats). Mild upset stomach (in dogs).

  • Cycad palms: Vomiting and liver failure, usually within two to three days.

  • Oxylate plants: Mouth and facial swelling, difficulty breathing, and vomiting.

Prevention Tips

Avoid keeping these types of plants in your yard or house. And don’t forget to inspect bouquets for lilies, especially during spring. If your pet has eaten an oxalate plant, feed it milk to help reduce the swelling, and then call your vet.