Kittens are dewormed on an age grid, not on a symptom: at 2, 4, 6 and 8 weeks, then every 2 weeks until 12 weeks, which is 6 treatments across 10 weeks. Not one of those 6 is a dose. The molecule and the amount come from a vet who has weighed that kitten the same morning, because product labels start at different ages and a 300 g body has almost no room between effective and toxic. Two fecal exams, 1 at 4 weeks and 1 at 14 weeks, decide whether the grid actually cleared the litter.
Six Treatments in Ten Weeks
The 14-day interval comes from how roundworm moves through a litter, not from the calendar looking tidy. Toxocara cati larvae sit dormant in the queen's muscle and wake up during lactation, so kittens can be infected through milk from day 1 and again at every nursing bout for 6 to 8 weeks. The prepatent period, infection to eggs in the stool, runs about 3 to 5 weeks in a kitten. Treat at 2 weeks and you kill the worms already present; worms swallowed on day 14 are not laying eggs yet and survive the dose. That is why 1 treatment does nothing lasting and why the gap is 14 days rather than 30.
The Age Grid
| Age | Treatment | Days since last | Fecal exam |
|---|---|---|---|
| 2 weeks | 1 of 6 | none | not useful, prepatent |
| 4 weeks | 2 of 6 | 14 | sample 1, before the dose |
| 6 weeks | 3 of 6 | 14 | no |
| 8 weeks | 4 of 6 | 14 | no |
| 10 weeks | 5 of 6 | 14 | no |
| 12 weeks | 6 of 6 | 14 | no |
| 14 weeks | none | 14 after the last | sample 2 |
Put the grid on the same sheet as the birth dates. A litter of 5 born on a Tuesday gets 5 lines and 1 shared calendar. Push the 4-week treatment to 5 weeks because the weekend was busy and the remaining 4 treatments slide with it, leaving a 21-day hole. Unknown birth date? Age the kittens by weight and eyes: eyes open at 7 to 14 days, and that alone pins the start inside a 7-day window.
Why No Dose Appears in This Article
Between 2 and 12 weeks a kitten goes from roughly 300 g to 1.2 to 1.5 kg, a 4 to 5 fold change, so any fixed amount is wrong across most of the window. Minimum ages differ by product: some pyrantel suspensions are labeled from 2 weeks, most spot-ons from 8 to 9 weeks, and many combination tablets from 6 weeks and 0.5 kg. A vet picks the molecule for the parasites the fecal exam actually showed, then converts per kilogram of measured weight, and the prescription is the only legal route. Two rules follow from that. Do not break a tablet by eye to build a small dose, ask for the pediatric suspension. Do not bring the next treatment forward because a kitten still looks thin, the 14 days exist to protect a liver that is 1/20 of adult size.
Fecal Exam One: Week 4
Collect 2 to 5 g of fresh stool, about a thumbnail, bag it, and deliver within 12 hours, refrigerated if there is a delay. Zinc sulfate flotation is the standard test and finds Toxocara, hookworm and tapeworm eggs. Giardia needs an antigen test or a direct smear, since cysts are small and shed intermittently. Know the limit: a kitten infected 10 days ago sheds nothing yet, so a negative at 4 weeks means no patent infection today, not no worms. Repeat the same test at 14 weeks, 14 days after treatment 6, when the last larval cohort has matured. Two negatives 10 weeks apart, at 4 and 14 weeks, justify quarterly screening from 6 months. One negative justifies nothing.
Records: Four Columns, One Scale
Log 4 fields per kitten: weight to the nearest 5 g, treatment date, product name with lot number, and each fecal result. The lot number earns its space. If 2 of 5 kittens vomit within 2 hours, the clinic can check the batch instead of guessing. Weekly weighing is enough here, 10 to 11 points across the grid, and it catches the kitten that is falling behind before the coat goes dull. At 4 to 8 weeks, less than 60 g of gain across 7 days is a vet call, and so is any drop on any single day after day 3.
The Environment Does Half the Work
Deworming a kitten in a contaminated nest produces a positive exam at 14 weeks anyway. Toxocara eggs are sticky and survive 1 to 2 years in soil, so treat every surface the queen has licked as positive. Scoop the box twice a day and do a full litter change every 3 days. Wash bedding at 60 C or above. Wipe hard surfaces with a 1:32 household bleach solution, 10 minutes of contact, then rinse. Bleach does not kill eggs on contact, it strips the sticky outer coat so the next wipe removes them, which is why 2 passes beat 1 long soak. Steam carpet at 65 C or higher, or close that room for 4 weeks. Keep kittens off garden soil until 12 weeks, a sandbox is a very large litter tray.
Reactions That Need a Call Today
Drooling for 10 to 20 minutes after an oral dewormer is common and needs nothing. Call the same day for vomiting 2 or more times in 24 hours, drooling past 2 hours, a staggering walk or wide pupils, diarrhea 3 or more times in 24 hours, 24 hours without food, or a kitten that feels cold to the touch. Bring the box, the product name and the weight you logged that morning. A pre-weaning kitten dehydrates inside 24 hours, so one day of waiting is a genuine risk at 400 g.
Five Steps for This Week
- Write the 6 dates on the nest sheet now, counting 14 days apart from the 2-week mark to 12 weeks.
- Book the 4-week fecal exam and the 14-week repeat on the same day you book the first treatment.
- Weigh each kitten weekly to 5 g and paste the numbers next to the dates, not in a phone note.
- Set the litter routine at 2 scoops a day and a full change every 3 days, bleach wipe on the same day.
- Ask the vet for a written dose per kitten, with the weight it was calculated from, and keep it with the lot numbers.
Sexing is the other job that lands in the same week and it needs 1 cm against 2.5 cm at 3 weeks, see kitten sex identification. For hands-on time with the litter, the useful window is day 3 to 16 in 5-minute blocks, covered in the kitten handling window. What 6 treatments plus 2 exams cost is laid out in the cost tools.
Frequently asked
Can I start deworming at 4 weeks instead of 2?
Only if a vet agrees for that litter. Starting at 4 weeks leaves 14 days in which milk-borne larvae already present at birth go untreated, and those worms can double the fecal egg load by the second exam. If the queen was not treated before birth or her history is unknown, the earlier start is the safer schedule, and the vet sets the product for a kitten that may weigh under 350 g.
Do I need a fecal exam if every kitten looks healthy?
Yes, because appearance lags infection by weeks. A kitten can carry a moderate roundworm load and still nurse and play, so the only way to know whether 6 treatments worked is a sample at 4 weeks and a repeat 14 days after the last one. Negatives at 4 and 14 weeks let you move to quarterly screening from 6 months instead of guessing from body shape.
What if one kitten vomits after the treatment?
A single vomit within 2 hours may mean the dose came back up, so call the vet before giving anything else rather than repeating it yourself. Two or more vomits in 24 hours, drooling past 2 hours, wobbling, or 24 hours without food are same-day problems. Record the lot number and the weight so the clinic can judge whether the dose or the batch is the issue.