Diphenhydramine (Benadryl)

Caution

Verdict

Do not self-medicate. If a cat ate a human tablet, call a vet — this site will not give a dose.

Toxic principle: antihistamine (overdose causes sedation or excitation; this site does not give doses)
Also called: benadryl, unisom, allergy pill
Source: ASPCA · Verified 2026-08-13

Verdict

Veterinarians sometimes use diphenhydramine. That is not permission to dose from the bathroom cabinet. Human tablets vary in strength; some “PM” products add acetaminophen; some liquids add alcohol. Overdose causes sedation or, paradoxically, agitation.

Symptoms to watch for

  • lethargy
  • wobbliness
  • agitation
  • drooling

What to do

Do not give another dose. Call a vet or poison control. Read the box for extra ingredients like acetaminophen.