Why broth makes this riskier than dry powder
A liquid form means your cat likely ingested more 5-HTP than if they'd encountered the powder alone. The chicken broth masked any bitter taste, encouraging them to lap up every drop. For a 4.5 kg cat, even trace amounts can trigger neurological effects—watch closely for dilated pupils or sudden sensitivity to light, which often appear before tremors.
Check the supplement's inactive ingredients now. Many contain xylitol as a sweetener, which is deadly to cats even in tiny amounts. If the bottle lists 'natural flavors' or 'proprietary blend,' assume the worst and head to the vet—these often hide additional stimulants.
Timing matters with serotonin spikes
Since this happened last night, the first 12-hour window is critical. Serotonin syndrome symptoms often start with subtle restlessness before escalating to vocalizing, stumbling, or rigid limbs. Your cat's small size means their system can't dilute the compound effectively—don't wait for severe signs to develop.
Collect any vomit or diarrhea in a bag for the vet. Even if it's just broth now, the color and consistency help gauge how much 5-HTP was absorbed. Note any changes in litter box habits—straining or unusual postures can indicate abdominal pain from gastrointestinal effects.
What your vet needs from you immediately
Bring the supplement bottle itself, not just a photo. The vet needs to see the exact milligram strength and lot number, which are often missing from online listings. If the bottle lists '5-HTP extract' rather than pure 5-HTP, the concentration could be much higher than the label suggests.
Describe the broth's volume and how much was left. 'Lapping the bowl' could mean anywhere from a teaspoon to a quarter cup—every detail helps the vet calculate potential exposure. Mention if your cat has ever had flea/tick meds recently, as some interact dangerously with serotonin boosters.
Home monitoring between now and the vet
Turn off bright lights and reduce noise. Overstimulation worsens serotonin syndrome—keep them in a quiet, dim room. Avoid petting or handling unless necessary, as touch can trigger agitation in affected cats.
Check gum color every 30 minutes. Pale or bright red gums indicate circulatory stress. Time their breathing rate by counting chest rises over 15 seconds—normal is 20-30 breaths per minute. Faster rates, especially with open-mouth panting, mean immediate transport to the ER.
The step-by-step response, from the first minute to the vet visit, is in our 5-HTP & Herbal Supplements emergency guide.