Why loose stool isn't your main concern with yew
While the loose stool might seem like the immediate problem, it's actually one of the milder signs of yew poisoning in your 12 kg dog. The real danger comes from how taxine alkaloids interfere with heart function — they can cause irregular rhythms or even stop the heart without obvious digestive symptoms first. What you're seeing now could just be irritation from swallowing plant matter.
Watch closely for muscle tremors, stumbling, or sudden lethargy — these indicate the toxins are affecting the nervous system. Since your dog chewed the sprig yesterday, the critical 6-12 hour window for severe cardiac symptoms has passed, but any new weakness warrants an emergency vet visit immediately.
How body weight changes the risk level
At 12 kg, your dog is in a middle range where even a few sprigs could be dangerous — smaller dogs show symptoms faster, but larger ones aren't completely safe either. The taxine dose isn't strictly weight-dependent because the alkaloids attack specific heart cell channels, so a small amount can still disrupt normal function.
Unlike some toxins that cause vomiting as a first sign, yew often affects the heart before the stomach. If you see pieces of the sprig in the stool, that confirms ingestion but doesn't mean the dangerous compounds have passed through — they absorb quickly into the bloodstream.
What to do about delayed symptoms
Since it's been over 12 hours, the highest risk period for acute cardiac arrest has diminished, but delayed weakness or breathing trouble could still appear. Keep your dog rested in a quiet space — any exertion stresses an already compromised heart. Check gum color frequently; pale or bluish gums signal oxygen circulation problems.
Don't induce vomiting at this stage — the toxins absorb too quickly for that to help, and the stress of vomiting could further strain the heart. Hydration is important with loose stools, but only offer small amounts of water at a time to avoid stomach distension.
When loose stool becomes an emergency
If the stool changes from simply loose to containing blood or mucus, that suggests intestinal lining damage from sharp sprig fragments. More urgent are any respiratory changes — rapid shallow breathing or exaggerated chest movements mean the heart isn't pumping efficiently.
Time matters less now than symptom progression. Even if the chewing happened yesterday, new neurological signs (head tilting, dilated pupils) or collapse mean immediate vet care is critical — there are no effective home treatments once the toxins circulate.
The step-by-step response, from the first minute to the vet visit, is in our Yew Plant Toxicity in Dogs and Cats emergency guide.