Everything You Need to Know About Cat Deworming

1 Overview

Why deworm?

Internal and external. Don’t say ‘mine never goes out.’ Cats love insects and cockroaches; eaten bugs carry bacteria and parasites that lodge in the gut.

So regular deworming is necessary!

What age?

At about 8 weeks (2 months) for the first external deworming.

To be safe, start internal at 3 months.

Note: the first vaccine is at 2 months, so avoid deworming about 1 week before or after.

How often?

Internal at least every 3 months; if raw food, shorten.

External: summer 1/month, winter 2–3 months.

What products?

Internal+external: a selamectin spot-on

Effect: treats roundworm/hookworm/sarcoptic mite/flea/lice, prevents heartworm (not tick or tapeworm)

Internal+external: a combined spot-on (imidacloprid + moxidectin)

Effect: prevents and treats ear mites, kills fleas, clears gut nematodes, prevents heartworm (not lice, tick, or tapeworm)

Internal+external: a broad-spectrum spot-on (eprinomectin + praziquantel)

Effect: treats tick/roundworm/hookworm/tapeworm/flea (not lice, mite, or heartworm)

External-only: a fipronil product

Effect: prevents lice/tick/flea adults, larvae, eggs (not mite, hookworm, roundworm, heartworm)

Correct dosing

Internal

1. Hide the pill in can or treat to trick the cat

2. Hold the jaw open, place at tongue base, close mouth, stroke throat to swallow

3. Use a pill shooter

External

Part neck fur, drop on skin (not fur), smooth fur (one dose per cat, no sharing)

Symptoms suggesting parasites

1. Running before or after defecation, dragging the rear, frequent anal licking

2. Vomiting or diarrhea, sometimes noodle- or rice-like worms

3. Fungal infection or large rash on skin, frequent biting of body parts

4. Soft stool, watery diarrhea, even blood (or diarrhea then constipation)

5. Raised temperature, hot ears

6. Poor appetite, lethargy, thinness, pale mucus

7. Swollen belly but not eating—’fat’ (worms breeding, causing inflammation)

If abnormal, see a vet; don’t medicate blindly.

Don’t deworm in these cases

1. When stress is likely, e.g., new home or environment change

2. With vomiting, diarrhea, discomfort, or during illness

3. Anemia, thinness, malnutrition

4. Generally within a week of vaccination, to avoid reactions

5. Severe skin disease—avoid external deworming

6. Pregnant cats: if no worms found, avoid; if must, use a pregnancy-safe product

Summary: we use a selamectin spot-on plus a chewable most; choose by your cat’s needs.