Why is this dangerous?
5-HTP raises serotonin directly and is one of the supplements most often reported to cause serious poisoning in dogs — tremors, seizures and serotonin syndrome.
St John’s wort, ephedra, guarana and bitter orange (synephrine) act like antidepressants or stimulants. Because supplements are unregulated, the actual content can be far above what the label says.
Why speed matters
Delaying care significantly worsens outcomes. Some signs appear hours or days later, so "looks fine right now" is not a reason to wait.
Signs to watch for
- Agitation, restlessness, confusion
- Tremors, twitching, rigidity
- Fast heart rate, panting, high temperature
- Vomiting, diarrhoea
- Seizures, collapse (emergency)
What to do right now
- Call your vet or a poison line and read the ingredient list aloud.
- Bring the bottle — “proprietary blend” labels often hide stimulants.
- Do not give any other supplement or medicine to calm the pet.
- Keep all supplements in a closed cabinet, treat them exactly like prescription drugs.
If your pet shows any of the signs above, go to the nearest emergency vet now and call ahead.
The step-by-step response, from the first minute to the vet visit, is in our 5-HTP & Herbal Supplements emergency guide.