Visiting Vet: Did she or didn’t she?

What happens when your pup ingests a mothball.

Products to repel moths come in many forms, and can contain different toxic ingredients.

One thing about being a veterinarian, it’s rarely dull. Well, honestly, after 40 years I’m a little tired of fleas and ticks, and vomiting and diarrhea, but we are always assured of a little excitement, thanks to pets’ unending propensity for getting into trouble. Take Woolie, for example. This young Labrador retriever mix was out in the yard when her owner spotted her with something in her mouth. Something white. Something that looked like it might be a mothball.

Mothballs always make me think of my grandmother, Lena. The scent evokes a cozy nostalgia that oddly goes along with the smell of her cinnamon and sugar cookies baking in the oven, and the way she saved rubber bands on doorknobs in her Brooklyn apartment. Unfortunately for Woolie, ingesting mothballs is a long way from eating Grandma’s cookies.

Products to repel moths come in many forms — balls, cakes, crystals, and flakes — and may contain different toxic ingredients, including naphthalene, paradichlorobenzene, or camphor. Woolie’s owners were not completely sure she had actually eaten one. They tried to find the package to identify the product, but could only find some loose mothballs. Their first thought, understandably, was to make her throw up. After two doses of hydrogen peroxide administered at home, Woolie upchucked her food from earlier in the day, but there was no sign of the mothball. At this point the family reached out to their veterinarian, who referred them to me, as I was the doctor on call for emergencies that day. I, in turn, advised they consult the Pet Poison Hotline and get back to me if the toxicologist thought an emergency visit was warranted.

If your dog downs a mothball, and you don’t know what kind, there are simple tests you can do at home. Start by dropping the ball into room-temperature water. Camphor balls float. If ingested, camphor is rapidly absorbed into the system. Clinical signs typically appear within five to 90 minutes, and may include vomiting, diarrhea, abdominal pain, depression, restlessness, and in severe cases, seizures and coma. Camphor, however, is not that commonly marketed in moth-repellent products in this country. Woolie’s family’s mothballs did not float.

If the mothball sinks in plain old water, your next diagnostic step is to make a saturated salt solution, mixing 3 tablespoons of regular salt in a half-cup of warmish water until it dissolves. Now drop your mothball in that concoction. If it sinks, it’s paradichlorobenzene, the least toxic possibility, and one that rarely causes serious problems. Woolie’s family’s mothballs did not sink. Mothballs that float in a saturated salt solution are naphthalene, the most common kind of mothball in the U.S. Like camphor, naphthalene is rapidly absorbed when ingested. Signs may include vomiting, lethargy, loss of appetite, seizures, anemia, weakness, collapse, and coma.

Treatment depends on the exact product ingested, amount ingested, size of dog, and presenting symptoms. Woolie’s family did an admirable job playing forensic scientist, as directed by Pet Poison Control. The mothball floating in a salt solution confirmed it was naphthalene. The first toxicologist was worried enough about the more drastic toxic effects that naphthalene ingestion can cause that she recommended the pup come see me.

When Woolie arrived, I examined her carefully. It was already almost 90 minutes since she was seen with “something white” in her mouth, but Woolie was as happy and carefree as a kid at the beach. While I didn’t necessarily expect her to seem sick yet, what I was expecting was for her breath to smell like … well … Grandma’s mothballs. I took off my face shield and delicately sniffed Woolie’s mouth. Nothing. I sighed and took off my surgical mask (which my assistant and I both wear whenever working close together). I took a deeper sniff. Nothing. Finally I opened her mouth wide, doing my best impression of a lion tamer putting her head in the jaws of the beast, and took a deep snort. Nothing but puppy breath. No mothballs. No Grandma.

I called the owners who were waiting outside in their car, observing our social distancing protocol. “I don’t smell anything on her breath,” I said. “Are you sure she actually ate the mothball?” Her family demurred. They couldn’t be positive. They, too, commented that her vomit had not had that distinctive scent of mothballs. They were sure that if she had eaten any, it was only one ball. “Sit tight,” I said.

What is the toxic dose of naphthalene mothballs for a dog? I don’t know. I called the Pet Poison Hotline again. This time I got a different toxicologist. “What do you want me to do with this case?” I asked. “They aren’t positive she even ate the mothball. She doesn’t smell like mothballs … and for a dog weighing in at almost 50 pounds, is ingestion of one mothball enough to cause serious problems?” Here’s why we love the Hotline. They know all kinds of cool, handy facts, like the average weight of a mothball, which, they tell me, is 2.4 to 4.0 grams, rarely 5 grams. They know that the toxic dose of naphthalene for a dog Woolie’s size would be 8.7 grams. Great news! The second toxicologist decided that even if Woolie really had eaten one whole naphthalene mothball, it was very unlikely to cause the more dire toxic effects. We could all relax a bit. It was, however, possible that one naphthalene mothball could cause significant gastrointestinal irritation.

We gave Woolie the recommended injection of a medication to calm her stomach, and sent the owners home with five days’ worth of gastric protectants, antacids, and instructions to consult their regular veterinarian should she show any other signs over the next few days. Never a dull moment. Now I’m feeling a bit nostalgic. Maybe I’ll go bake some of Grandma Lena’s cinnamon and sugar cookies.