Big Head always ate his veggies. Tall, lean and so black that his features were almost indistinguishable, the 12-year-old cat "was a beast for greens," say his owners, Greg and Jessica Ealick of Baltimore. He raided celery sprouts from the crisper bin and stealthily snatched lettuce from sandwiches. But Big Head's weakness was also his downfall: In April, he nibbled on an Easter lily -- and died. It's a fate that befalls too many pets: Hundreds of common plants -- from daffodils to yew trees -- are toxic to animals. Luckily, you can take steps to keep your pet safe.

1Learn what's harmful

The American Society for the Prevention of Cruelty to Animals keeps a comprehensive list of toxic plants and their effects at www.apcc.aspca.org -- and some of the info there may surprise you. Big Head didn't know it, but the tiniest nibble on a lily can cause kidney failure in cats. For birds, warns Jeff Newman, a veterinarian at Caring Hands Animal Hospital in Arlington, "the big thing is avocados." Poinsettia, however, is "highly overrated" as a toxin, according to Dana Farbman, a licensed veterinary technician at the ASPCA's Animal Poison Control Center. It does cause stomach upset, but "it's not as dangerous as popular legend would have it." Keep in mind that dangerous plants won't necessarily come into your house as foliage: If Tweetie's perch is made from a tree branch, make sure it's nontoxic. And ask your vet whether the greens you're feeding your reptile, bird or rodent are safe.

2Watch for symptoms

This is harder than it sounds: Unfortunately, there are almost as many reactions to poisoning as there are toxic plants, and some may not set in immediately (the effects of certain ivies can take weeks or months to appear). Major symptoms include vomiting, diarrhea, seizures, depression or hyperactivity, difficulty breathing, and even kidney failure or cardiac arrest. Because rabbits and other rodents are generally stoic creatures, lethargy may be the only sign that they're sick.

3Call in the pros

You should always have a pet poison safety kit on hand (the ASPCA site lists items to include). But you also shouldn't hesitate to seek help if a pet is acting abnormally, Newman says. If you suspect poisoning, immediately call your vet or dial the ASPCA's 24-hour poison control hotline at 888-426-4435 (it charges $50 per case, which includes emergency advice and all follow-up conversations). If the poisoning isn't serious, the hotline could help you avoid a trip to the vet. The more details you can provide, the better: the type of poison ingested, how much and when, the symptoms, and basics such as your pet's breed, age and weight. Knowing the scientific name of the plant (usually found on plant tags) is also a huge help. If you must take your pet to a vet, the hotline will identify the nearest emergency clinic and call ahead, "so the vet can have a game plan in place," Farbman says.

4Use safe alternatives

Many household pets like to snack on greenery but lack the instincts that would keep them away from the dangerous stuff. "If they eat your houseplant," says Cindy Spak, owner of GreenSpace Unlimited Garden Center in Alexandria, "it's usually because they're missing [a nutrient], or they need to throw up." Spak -- whose nursery is home to 12 cats -- recommends giving them pet grass (aka Dactylis glomerata). Chock full of nutrients, it's perfect for when your cat or dog needs to nibble.

Emily Messner

The grass is always greener when you're not supposed to eat it. (Sigh.)