SALT LAKE CITY, Utah – When the Johnson’s added a chocolate lab to their family two years ago, they knew they were going to have their hands full. They say nothing keeps the 2-year-old dog away from the water.

“Millie loves swimming and loves the outdoors,” Travis Johnson, Millie’s owner said.

This weekend, the family took her up to Dog Lake in Mill Creek Canyon, a popular spot for dog owners, to cool off. Their routine trip took a turn for the worse when she fell violently ill.

“At first, it was great. Millie loved playing in the water once we got to the top,” Johnson said. “But as we were leaving, something wasn’t right.”

Johnson said on the hike down Millie started vomiting and her pupils began to dilate.

“She was basically limp,” he said. “She was breathing very shallowly and just so much salivation.”

Millie collapsed about a mile from their car. Johnson picked her up and carried her the rest of the way. The family rushed to the vet hospital.

Johnson said the veterinarian immediately tested for water toxicity, but results steered them away from that theory.

“They were able to rule that out,” he said. “But they weren’t able to say if she ate a mushroom or could there have been some algae possibly up there. They said unlikely given the elevation but still possible.”

They posted their experience of Facebook only to learn of another dog that went up to the same lake Sunday and had the same symptoms. Since the trail to the lake just opened this weekend, the family is using their story to warn other dog owners this summer.

“At the first thing you notice that’s not normal, pay close attention, because I let her go a little bit longer than I probably should,” Johnson said.

Millie is expected to make a full recovery after taking medication for the next week.