Human medicines that poison cats

Never — a single regular-strength tablet can kill a cat.

Ibuprofen

Never — NSAIDs ulcerate the gut and injure feline kidneys.

Naproxen (Aleve)

Never — a long-acting NSAID with the same gut and kidney risks as ibuprofen.

Aspirin

Never give leftover aspirin. It is an NSAID and cats clear salicylates slowly.

5-fluorouracil cream

Never — tiny amounts of 5-FU cream are often fatal to cats.

Topical

Vitamin D3 (cholecalciferol)

Dangerous — extra vitamin D raises calcium until the kidneys fail.

ADHD and stimulant medicines

Dangerous — amphetamines and related stimulants cause life-threatening agitation.

Topical NSAID creams

Dangerous — cats lick diclofenac and similar gels off skin and furniture.

Topical

SSRI antidepressants

Toxic in overdose — serotonin syndrome is an emergency. Do not start these at home.

Cannabis and CBD

Toxic — THC makes cats wobbly and miserable. CBD is not automatically safe.

Other exposures

Nicotine and vape liquid

Toxic — concentrated vape juice is the high-risk form.

Other exposures

Iron supplements

Toxic — elemental iron in adult or prenatal tablets can damage the gut and liver.

Thyroid medication

Toxic in overdose — too much thyroid hormone or methimazole is a vet problem, not a home adjustment.

Blood-pressure medication

Toxic in overdose — the cat can become profoundly weak or collapse.

Birth-control pills

Caution

Caution — a few pills usually cause stomach upset, not a hormone crisis. Still call if a pack is missing.

Diphenhydramine (Benadryl)

Caution

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

Melatonin

Caution

Do not self-medicate. If ingested, call a vet — check the label for xylitol.