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Dog ate 5-HTP supplements? Toxic: what to do now

5-HTP mood and sleep supplements can cause serotonin syndrome in dogs, with tremors, seizures, high temperature and even short-term blindness.

If your dog ate or touched this, call your vet or a pet poison line now

United States

ASPCA Poison Control+1 (888) 426-443524/7, 365 days a year · A consultation fee may apply · Run by the ASPCA for pet owners and vets.
Pet Poison Helpline+1 (855) 764-766124/7 · A fee applies; their website has the current price · Serves the US, Canada and the Caribbean.

Poison lines in other countries: United Kingdom, Canada, Australia, New Zealand, Belgium, France, JM, PR, Singapore, Switzerland, TT, VI

United Kingdom

Animal PoisonLine+44 1202 50900024 hours a day · A fee applies; their website has the current price · Run by the Veterinary Poisons Information Service for pet owners; for collapse, fits or breathing trouble, call your vet.

Canada

Pet Poison Helpline+1 (855) 764-766124/7 · A fee applies; their website has the current price · Serves the US, Canada and the Caribbean.

Australia

Animal Poisons Helpline1300 869 73824/7 · From A$79 per consultation; their website has the current price · Staffed by poisons information consultants with emergency vet or pharmacy backgrounds.

New Zealand

NZ Animal Poisons Helpline0800 869 73824/7 · Charges apply · The NZ National Poisons Centre does not advise on animals and refers pet owners here.

Belgium

Centre Antipoisons / Antigifcentrum070 245 245Animal questions: weekdays 8:00 to 16:00; weekends and public holidays 10:00 to 16:00 · Free call · Human poison center that also takes animal questions; human emergencies get priority, so call your vet first.

France

CNITV (Centre National d'Informations Toxicologiques Vétérinaires)+33 4 78 87 10 408:30 am to midnight, every day · Veterinary poison center that answers vets and pet owners; call your own vet first if you can.

JM

Pet Poison Helpline+1 (952) 853-171624/7 · A fee applies; their website has the current price · Serves the US, Canada and the Caribbean. This is the number it gives for other Caribbean islands; it also lists a toll-free number for the Caribbean, +1 (877) 416-7319.

PR

Pet Poison Helpline+1 (877) 416-731924/7 · A fee applies; their website has the current price · Serves the US, Canada and the Caribbean; this is its toll-free number for callers in the Caribbean and the US Virgin Islands.

Singapore

Animal Poisons Helpline+65 3106 421624/7 · Ask about the fee when you call · Australia-based animal poison service; this is the Singapore number listed on its site.

Switzerland

Tox Info Suisse14524/7 · Swiss poison center that also tells owners how risky an animal exposure is; from abroad call +41 44 251 51 51.

TT

Pet Poison Helpline+1 (952) 853-171624/7 · A fee applies; their website has the current price · Serves the US, Canada and the Caribbean. This is the number it gives for other Caribbean islands; it also lists a toll-free number for the Caribbean, +1 (877) 416-7319.

VI

Pet Poison Helpline+1 (877) 416-731924/7 · A fee applies; their website has the current price · Serves the US, Canada and the Caribbean; this is its toll-free number for callers in the Caribbean and the US Virgin Islands.

Find an emergency vet

5-HTP supplements and dogs: key facts

Verdict: Toxic · Emergency: get help now
What it can do: Tremors, seizures, wobbly walking, sleepiness or dullness and overreacting to touch or sound. All 8
How fast: 1 to 4 hours
What to do now: Call your vet or a pet poison line now. All steps
Sources: Merck Veterinary Manual. Reviewed 9 October 2026.

What should I do if my dog ate 5-HTP supplements?

Call your vet or a pet poison line now.
Keep the bottle and bring it with you.
Call before signs start if you can. Vets have more options early on.

Don't

Don't make your dog vomit unless a vet tells you to.

Symptoms to watch for

Tremors
Seizures
Wobbly walking
Sleepiness or dullness
Overreacting to touch or sound
High body temperature
Big pupils or short-term blindness
Vomiting, diarrhea or crying out

When signs appear: 1 to 4 hours

Why

5-HTP is a building block of serotonin, a brain chemical. Too much can overload the brain and nerves, a problem called serotonin syndrome.

Sources

Guide reviewed 9 October 2026. Page updated 7 November 2026.

General information from the sources above, not a diagnosis. When in doubt, call your vet.