Uncharacteristic sluggishness, unsteady gait, drooling, heavy breathing, diarrhea, seizures, and sudden bouts of vomiting are among the common clinical signs of feline poisoning (toxicosis). A cat owner who observes any of these signs will do an animal a huge favor by seeking emergency veterinary care. Immediate treatment may be the only way the cat’s life will be saved.

According to the American Society for the Prevention of Cruelty to Animals (ASPCA), the following are among the most frequently identified causes of feline poisoning: insecticides that are used on lawns and gardens; rodenticides, which are used to kill rats and mice; household cleaning agents, such as bleach; antifreeze that is spilled and subsequently ingested; and lead, once a common ingredient of house paint that is now found mainly in older homes. But the list of potential poisons—or toxins—goes well beyond those five categories to include many other substances that are commonly used in the typical home.

Each year, the ASPCA’s Animal Poison Control Center processes well over 100,000 phone calls concerning substances that are potentially poisonous to household pets. While some calls come from cat owners seeking general information about feline poisons, others are from people who fear that their cats have ingested a toxic substance and are seeking guidance regarding emergency treatment.

Following are the 10 categories of potentially deadly substances found in or near the home that are most frequently asked about by callers to the ASPCA center:

• Human medications. Some cold relievers, antidepressants, dietary supplements, and pain relievers—most notably such commonly used substances as aspirin, acetaminophen (Tylenol®), and ibuprofen are a common cause of feline poisoning. Cats are apt to swallow pills that have been left on night stands or counter tops or have been accidentally dropped on the floor.
• Insecticides. Cats can be poisoned by certain products that were designed specifically for dogs as a means of killing fleas, ticks, and other insects.
• Human food. Ingestion of many tasty substances, such as grapes, onions, raisins, avocados, and chewing gum that contains a sweetening chemical called xylitol, can be severely disabling to a cat. Chocolate—especially baker’s chocolate—is particularly dangerous, since it contains chemicals that can potentially cause abnormal heart rhythms, tremors, depression, and seizures.
• Indoor and outdoor plants. Lilies, tulips, foxglove, and philodendron are among hundreds of plants that are known to be poisonous to cats. Ingesting just a small leaf of some common ornamental plants such as poinsettias could be enough to make a cat ill, and swallowing a sizable amount could prove fatal. Lilies are especially toxic to cats; they can cause life-threatening kidney failure if ingested even in tiny amounts.
• Veterinary medications. Although created for household animals, such preparations as nonsteroidal anti-inflammatory drugs (NSAIDs), heartworm preventatives, antibiotics, and nutritional supplements can be toxic if improperly administered.
• Rodenticides. Substances that are designed to poison mice and rats contain ingredients that may be attractive to a cat as well. Depending on the type of rodenticide, ingestion can lead to such potentially life-threatening conditions as internal bleeding, seizures, and kidney damage.
• Household cleaners. Products such as bleach, detergents, and disinfectants can cause severe gastrointestinal and respiratory tract distress if swallowed by a cat.
• Heavy metals. Lead, zinc, mercury and other metals may pose a severe threat if ingested or inhaled. Lead is especially dangerous, since cats are exposed to it through many sources, such as paint chips, linoleum, and dust produced when surfaces in older homes are scraped or sanded. Zinc is present in pennies minted after 1982 and ingestion of even a single penny may result in potentially fatal anemia and kidney failure.
• Garden products. Fertilizers, for example, can cause severe gastric upset and possible gastrointestinal obstruction if ingested.
• Chemical hazards. Such products as ethylene glycol antifreeze, paint thinner, and swimming pool chemicals can cause kidney failure, gastrointestinal upset, respiratory difficulties, or chemical burns.

The lethal potential of these and other poisonous substances depends on several factors: the amount of a toxic substance that is inhaled, ingested, or in some other way enters a cat’s system; its inherent potency; the age, size, and general health of an affected animal; and the way in which the substance is metabolized. An owner who suspects that a cat is showing signs of any type of poisoning, should contact a veterinarian immediately or call the ASPCA’s Animal Poison Control Center at 888-426-4435 (have a credit card handy as there may be a charge for the call). Importantly do not try to induce the animal to vomit unless specifically instructed to do so.