In the past few years, more items have been added to the list of dangerous toxins for dogs. It is important to know everything that you should to keep your dog away from potentially harmful substances. As always, if you suspect your pet has eaten any of the following foods or a plant in your backyard, try to note the amount ingested and contact your veterinarian or the ASPCA Animal Poison Control Center at (888) 426-4435 or Pet Poison Helpline at 1-800-213-6680. Have these numbers posted somewhere in the event of an emergency. Staff is available 24-7. I do mention cats, but mainly focus on dogs, so if you own a cat, please make sure you know what is dangerous for them, too. Some of the items listed below should never be given to your dog, while others are okay in small amounts. Reactions will differ from dog to dog, with some being able to tolerate more than others (this also depends on the size of your dog, diet, and overall health).

Acetaminophen, Aspirin, Ibuprofen

This popular OTC medication often used by people is found in Tylenol and other popular cold/flu and pain medications. While the drug is safe for humans, it has a very narrow margin of safety for dogs and cats. Do not give this to your pet for pain! Limited ability to metabolize  cyclooxygenase in the liver (especially in cats) makes them susceptible to poisoning. Signs to watch for include lethargy, swelling of the paws/face (in cats) difficulty breathing, brown/blue gums (in cats), vomiting, loss of appetite, black tarry stool, jaundice. Toxicity Rating: moderate to severe

Aspirin  is a common over-the-counter (OTC) anti-inflammatory (NSAID) used in both human and veterinary medicine. When used at appropriate doses in pets under the supervision of a veterinarian, aspirin is used for pain management, for osteoarthritis, and clot prevention. However, when aspirin (or its similar salicylate-containing compounds) are inappropriately ingested, it can result in severe poisoning in dogs and cats. Sources of aspirin include Pepto-Bismol®, topical medications (shampoos, medications for acne, warts, calluses, etc.), make-up (e.g., foundations and concealers), and liniments (Bengay®, HEET®, Icy Hot, etc.). Symptoms of aspirin poisoning include vomiting, diarrhea, vomiting of blood, black-tarry stool, stomach ulcers, etc., hyperthermia, respiratory changes, bone marrow suppression, kidney failure,  collapse, extreme weakness, tremors, seizures, cerebral edema. Toxicity Rating: moderate to severe - can be life-threatening

Ibuprofen, found in NSAID medications such as Aleve, Motrin, and Advil, are common medications for humans for pain and inflammation. Veterinarians use ibuprofen based medications for our pets, but dosages and brands are very different. NEVER give any medication to your dog or cat without consulting your vet. Overdosing results in severe stomach ulcers, causing signs of vomiting, bloody vomitus, diarrhea, black tarry stool, weakness, pale gums (anemia), abdominal pain, lethargy, and loss of appetite. With larger ingestions, halitosis, kidney failure, liver failure, and neurological problems (e.g., tremors, seizures) can develop and can potentially be life-threatening. Toxicity Rating: moderate to severe - can be life-threatening

Alcoholic Beverages

For obvious reasons, alcoholic beverages and products containing alcohol should not be given to your dog. These include mixed drinks, beer, hard liquor, ethanol, and unbaked bread dough (also listed below). Ingestion of alcohol can cause dangerous drops in blood sugar and blood pressure and body temperature. Intoxicated animals can experience seizures and respiratory failure. Signs to watch for include excessive drooling, diarrhea, vomiting or retching, decreased coordination, central nervous system depression/weakness, hypotension (low blood pressure), tremors and hypothermia, coma, and death. Toxicity Rating: mild to severe

Avocado

The leaves, seeds, and bark of avocados all contain persin (a fungicidal toxin), which can cause vomiting and diarrhea in dogs and cats when eaten in large amounts. The fruit, which also contains persin, is okay for dogs in small amounts. Birds and rodents are especially sensitive to avocado poisoning, and it can be fatal. The greater risk to dogs is foreign body obstruction, which can occur  if a dog swallows the whole, large, round avocado seed. This seed can get stuck in the esophagus, stomach, or intestinal tract of dogs. Toxicity Rating: mild

Antifreeze (Ethylene Glycol)

This chemical, found in antifreeze, windshield de-icing agents, brake fluid, developing agents for photography, paints, solvents, and motor oils is extremely dangerous for both dogs and cats. It causes kidney failure. It is problematic because dogs are attracted to the sweet taste, but just a tablespoon for dogs and a teaspoon for cats can be fatal. Immediate treatment is necessary, or death can result. Recently, antifreeze and engine coolant manufacturers have agreed to voluntarily add bittering agents to reduce the appeal to animals. Signs to watch for include drunkenness, excessive thirst or urination, vomiting, sedation, halitosis, lethargy, coma, kidney failure. Toxicity Rating: severe to fatal

Batteries

For obvious reasons, batteries can be very dangerous when ingested by dogs. When punctured or swallowed, the alkaline or acidic material can leak out, causing severe corrosive injury and ulcers in the mouth, esophagus, and stomach. Note that ulcers in the mouth may not be observed for hours after ingestion. Immediate veterinarian attention is required. Symptoms include drooling, oral pain, pawing at the mouth, vomiting, loss of appetite, difficulty swallowing, abdominal pain, and inability to defecate, and fever. Toxicity Rating: moderate to severe

Magnets 

If your dog swallows a couple of magnets, they can attract and attach, causing a blockage. Keep magnets and magnetic toys out of reach of your dog.

Candy 

Candy, both sweetened and artificially sweetened, is bad for your pets. See Sweeteners and Xylitol below.

Chocolate, Coffee, Caffeine

There are several sources of caffeine in the house: in coffee, coffee grounds, tea, soda, energy drinks, weightlifter supplements, OTC pills (e.g., NoDoz), and diet pills. All of these contain methlyxanthines or theobromine. Darker chocolate is more dangerous the milk chocolate (it’s not “watered down”). White chocolate contains the lowest levels of methylxanthines, where bakers chocolate and raw cacao contains the highest. When ingested by dogs, it can cause vomiting and diarrhea, panting, excessive thirst and urination, hyperactivity, restlessness, abnormal heart rhythm, tremors, hyperthermia (elevated body temperature), seizures, and even death. Toxicity Rating: moderate to severe - can be fatal

Cocoa Mulch: a brown mulch used for landscaping is also very toxic.

Apple, Citrus and Pear Seeds, the Pits from Apricots, Cherries, Peaches, and Plums, etc., and Citrus Peels

A little sweet, a little tart—and also hazardous. Citrus plants contain citric acid, limonin, and oils that can cause irritation, and possibly even central nervous system depression, if ingested in significant amounts. The pulp part of the fruit typically does not pose a problem, for the oils reside in the peel of the fruit. Clinical signs include vomiting, diarrhea, depression and potential photosensitivity. Seeds from apples and pears contain arsenic and should be discarded before your pet eats these fruits (apples are good for dogs). The same goes for fruits that have pits, which can cause respiratory difficulties, coughing and sneezing.

Fruit Trees That Can Be Problematic

Apple Trees: All apple trees, including crab apple trees, are toxic to dogs. These trees are of the genus Malus and contain cyanogenic glycosides, a toxin that transforms into the poison cyanide when processed by stomach acid. The stems, seeds, and leaves contain this toxin. The toxin gets stronger when the tree is in the process of changing for autumn. When ingested in toxic amounts, clinical signs of dilated pupils, difficulty breathing, inadequate oxygen levels, bright red gums, shock, and death can be seen. Apple seeds contain arsenic and should not be given to your dog, but the apple itself is good for your dog and helps with dental health.

Apricot Trees: Similar in effect to apple trees, apricots contain cyanogenic glycosides. The effects of this toxin manifest as dark red mucous membranes, a lack of proper circulation throughout the dog's body, dilated pupils, constricted breathing, shock and if left untreated, death. Care should be taken to ensure proper help is sought if any part of these trees is ingested by your dog.

Fig Trees: The fig tree Ficus Benjamina contains proteolytic enzymes and psoralen. Proteolytic enzymes are microorganisms that break down proteins in the body. Psoralen sensitizes the body to light. When a dog brushes up against this tree, the skin becomes irritated. Ingestion of parts of this tree do not cause serious effects, but can lead to an irritation of the mouth, excessive salivation, and vomiting.

Lime Trees: The lime tree, Citrus aurantifolia, contains psoralens. The essential oils produced by the lime tree are also considered a toxic principle for this tree. Ingestion of the leaves, stems, or fruits of this tree can lead to severe irritation, sores of the mouth, enteric distress, depression, and a sensitivity to light.

Other Trees: Falling under the genus of Prunus, plum, peach, and cherry trees contain cyanogenic glycosides in all parts of their growth. The overall effects and warnings are similar for these trees, apricots, and apples. Ingestion of any part of these trees could become a veterinary medical emergency.

Grapes and Raisins and Currants

Just one snack box of raisins can be deadly to a 50-pound dog. All types of grape- or raisin- or currant- containing products (including grape juice, trail mix, bagels, etc.) can result in this. The toxicity is not necessarily dose-dependent, and symptoms can occur with even small ingestions. Pets usually look normal for a few hours, but most start throwing up within 12 hours. Symptoms include anorexia, vomiting, diarrhea, and potentially severe acute renal failure (which develops several days later). Once at this stage of toxicosis, hospitalization is necessary for a longer period of time because the dog is prone to renal failure. Toxicity Rating: moderate to severe

Grains can be fine or be a source of allergies (Cereal, Whole, and Derivatives)

Dogs that itch and chew at paws could have a food allergy. Many dogs who are suffering from allergies, ear infections, dental disease, compromised GI tract or immune system, UTI’s, and other health problems due to eating grains. Corn, wheat, and soy, which can be very high in pesticidal residue or contaminated with aflatoxins, are the largest culprits. If you choose to feed your dog processed kibble or wet dog food, choose one that is free of corn, wheat, and soy-free. This also goes for treats. Other grains should be fine in dog food unless your dog is gluten intolerant or has allergies. Just be sure that when you choose a grain-free dog food, it still has sufficient amounts of taurine to avoid heart issues as seen in recent studies with grain-free dog foods.

Macadamia Nuts

Depending on the amount ingested, these nuts can cause weakness, depression, severe lethargy, vomiting, tremors, and hyperthermia in dogs. Signs usually appear within 12 hours of ingestion and last approximately 12 to 48 hours. The toxic mechanism is unknown but can affect nerve function (specifically, the motor neurons, neuromuscular junctions, muscle fibers, or neurotransmitters). Toxicity Rating: mild to moderate

Milk

Pets do not have significant amounts of lactase, the enzyme used to break down lactose in milk, so consumption of milk can cause diarrhea and other digestive upset. Cheese, cottage cheese, yogurt,and kefir, on the other hand, can be very good in your dog’s diet.

Onions, Chives, Shallots, and Leeks

These foods can cause gastrointestinal irritation and can lead to red blood cell damage. Though cats are more susceptible, dogs are also at risk if large enough amounts are consumed, and Japanese breeds (Akita, Shiba Inu, etc.) are more sensitive than other breeds of dogs. Clinical signs of anemia may be seen, and include lethargy, pale gums, an elevated heart rate, and increased respiratory rate, weakness, exercise intolerance, and collapse. Onion and garlic poisoning may have a delayed onset, and clinical signs may not be apparent for several days. Toxicity Rating: mild to moderate

Paintballs

These marble-sized pellets contain polyethylene glycol. The components inside a paintball are “osmotically active,” which means when ingested, they can pull free water into the intestinal tract. That results in severe salt and electrolyte imbalances; untreated, this can be fatal. Dehydration and dangerously high concentrations of sodium, both affect the brain. Dogs who have eaten paintballs may look drunk, be disoriented, and develop seizures. Other symptoms include vomiting and diarrhea. Toxicity Rating: moderate to severe

Plants Toxic if Ingested

There are close to 400 plants that are known to be toxic in one-way shape or form to our pets, including sago palm, rhododendron, azalea, lily of the valley, oleander, rosebay, foxglove, nightshade family plants (leaves and stems), and kalanchoe. If you have plants in the house or backyard and you are not sure, “visit our full list” on the ASPCA Animal Poison Control Center website includes the names and photos of plants that can be dangerous to your pet. Also, be aware that many fertilizers, cocoa mulch, insecticides, and compost are harmful to your pets. Other plants can be allergens to dogs and cats.

Preservatives to Stay Away From

Chemical preservatives have been found to be toxic and cause many health problems, including cancer. Unfortunately, they are still being used in food for both humans and pets. Many processed dry and wet dog food and treats, including prescription dog foods, contain these toxic preservatives. Read your labels carefully and stay away from foods and treats preserved with BHA, BHT Ethoxyquin, Sodium Metabisulfite, Propyl Gallate, and TBHQ. 

Raw Foods (Fish, Pork, Eggs and Bones)

Raw meat and raw eggs can contain bacteria (salmonella and E. coli) that can be harmful. Raw fish and pork can contain parasites which can affect your dog’s health. Raw pork can cause trichinosis, a parasitic disease from raw and undercooked pork or wild game infected with the larvae of one species of roundworm. Fish meal in dog food can be preserved with ethoxyquin which is a powerful and lethal pesticide, and fish fed to dogs in large amounts can result in a thiamine (a B vitamin) deficiency that can lead to loss of appetite, seizures, and in severe cases, death.

Raw diets for dogs are a great and healthy way to feed your dog, but clean and careful handling must be practiced to prevent contamination, to your pet and you.! Make sure you are well educated on appropriate foods and handling/storing procedures for raw food diets. GSE rubbed on raw meats can help prevent the growth of harmful bacteria during storage.

Raw eggs also contain an enzyme called avidin that decreases the absorption of biotin (a B vitamin) that can lead to skin and coat problems. They can also be contaminated with salmonella. 2-5 raw eggs a week (depending on the size of your dog) in your dog’s diet will give your dog all the health benefits and is safe, but be sure to wash the egg thoroughly before cracking, especially if you plan to give your dog the shell.

Dogs love raw bones, and they can be helpful in keeping your dog’s teeth clean, but there are a couple of rules to follow: Watch your dog very closely when he is eating bones, they can choke, break teeth, and suffer severe injury should a bone splinter and become lodged in the throat or puncture your pet’s digestive tract. Never give your dog cooked bones. If you see your dog chipping or fragmenting the bone, take it away immediately, and be sure to get all the fragments that may be on the floor. Raw and smoked bones can give dogs GI upset if the dog has a sensitive stomach or is not used to that diet. GI problems can also occur due to Salmonella and E. coli.     

Salt

Large amounts of salt can produce excessive thirst and urination, or even sodium ion poisoning. Too much salty food can cause diarrhea, depression, tremors, elevated body temperature, seizures, and even death. Keep those chips to yourself!

Sweeteners

It is not necessary to add sweeteners to dog foods and treats. And if it is truly healthy for your pet, sweeteners and artificial coloring should be left out. Sweeteners also promote bacteria growth in the mouth, putting your dog’s oral health at risk and even the GI tract due to bacteria in the mouth being swallowed. Sweeteners like grains can be inflammatory, and others such as cane molasses, corn syrup, di-alpha tocopherol, fructose, sorbitol, sugar, pasteurized hone and unpasteurized honey (even organic) if it has been heated through steaming, cooking or baking are unhealthy sugars and can compromise the health of your dog making him more susceptible to cancer, allergies, hypoglycemia, nervous energy, tooth decay obesity and other health problems.

Tobacco and Marijuana (any hallucinogenic drug)

I think for obvious reasons, these are bad for your pet’s health. 

Vitamins (for Humans that Contain Iron)

Human vitamins are meant for humans, and you can actually damage your dog’s digestive system and other organs such as the kidneys and liver if you feed your dog these. If your dog is in need of a good dietary supplement, and this is especially important if your dog is on a commercial diet, NuVet vitamins and other natural supplements provide many healthy vitmins and minerals that kibble, wet dog food, and even home-cooked and raw meals may not provide. 

Walnuts (and other nuts and grains - risk of aflatoxins)

These can cause gastrointestinal problems, vomiting, and diarrhea. They can also cause respiratory issues such as excessive sneezing, coughing, and difficulty breathing. Prolonged storage of nuts and grains (especially corn and wheat but other grains, soy and legumes as well) can get contaminated with aflatoxins, a naturally occurring fungus. This is a growing problem in the business. Do not feed your pets animal-feed grade nuts and grains. Human grade peanuts and almonds in small amounts are good for dogs.

Xylitol (sweetener in diet/sugarless products, peanut butter, drinks, and gum)

This is an artificial sweetener found in gum, mints, foods, oral rinses, toothpaste, and diet/sugar-free products. It is absorbed into the bloodstream, and even just small amounts affect the pancreas causing hypoglycemia (a dangerous drop in blood sugar levels). Larger ingestion can result in liver necrosis and liver failure. Signs of xylitol poisoning include weakness, lethargy, collapse, vomiting, tremors, sudden on-set of seizures, jaundice, malaise, black-tarry stool, and even coma, and death if not treated quickly. Signs can appear as soon as 15 to 30 minutes after ingestion, but dogs can make a good recovery if treated immediately, before seizures become severe. (Photo: Little Layla recovering at home after spending a couple of nights in the emergency vet for ingesting sugar-free gum) Toxicity Rating: mild to severe - can be fatal.

Yeast, Yeast Dough, Baking Powder, Baking Soda

The dough can continue to rise and cause gas to accumulate in your dog’s digestive system. This can result in a bloated stomach which can progress to gastric-dilatation volvulus (GVD and also called “bloat”) where the stomach twists. This is a life-threatening condition. This can be painful and can cause stomach or intestines to rupture. Signs to watch for include excessive panting and drooling, vomiting, non-productive retching, distended stomach, elevated heart rate, weakness, collapse, and death. Leavening agents, if consumed in large amounts (in proportion with your dog’s size) can cause problems with electrolyte levels, muscle spasms, and/or congestive heart failure. Toxicity Rating: mild to severe

Safeguard your pets and pet and store dangerous items out of reach and childproof containers and behind closed doors.

Too Much of a Good Thing Can Be Bad...

Fat (in large amounts)

Fat is an essential component of a dog’s diet. But too much fat and large amounts of fat such as butter, margarine, lard, trimmings, and oil can cause health problems. Ingestion of excessive amounts of fat can cause liver failure and other organ damage. The amount of fat your pet needs is relative to the dog’s size, age, and overall health. 

Garlic (in large amounts)

Garlic provides amazing health benefits to dogs, but only when given the proper dosage, such as what might be found in pet foods and treats. Don’t give your dog additional quantities of garlic if on a good commercial diet that includes garlic. If you are feeding a raw diet or a home-cooked diet for your dog, make sure you know the proper amount to feed your dog. Use fresh, straight from the clove bud - nothing in a container, jar or can. Feed once a day for two weeks for it to build up in your dog’s system and then twice a week for maintenance. Dosage is as follows: 5 lb dog = 1/6 tsp, 10 lbs = 1/3 tsp, 15 lbs = 1/2 tsp, 60 lbs = 2 tsp, 120 lbs = 4 tsp. Make sure to use it with a healthy dog that is not on any medications. Check with your vet on any drug interactions and health concerns.

Liver and Other Organ Meats

These are very potent protein sources as well sources for other vital vitamins and minerals like phosphorus, iron, copper, magnesium, iodine, folic acid, and fat-soluble vitamins A, the B’s, D, E and K. Organ meat (not including the heart) should only comprise of 15% (liver 5%) of your dog’s total diet. Large amounts can cause Vitamin A toxicity and lead to kidney damage or failure.

Sources:

CJ Puotinen, The Encyclopedia of Natural Pet Care, McGraw Hill, New York, NY, 2000

http://www.petpoisonhelpline.com

http://www.vetmed.ucdavis.edu/ccah/health_information/plants_pets.cfm

http://www.aspca.org/pet-care/poison-control/plants/

http://www.vetmed.ucdavis.edu/whatsnew/article2.cfm?id=1809

http://www.aspca.org/pet-care/poison-control/animal-poison-control-faq.aspx#FD1