Natural deworming in dogs: does it work?
Do pumpkin seeds and herbs work as dewormers for dogs? An honest overview of evidence, risks and when a vet is needed.
Short & honest
Natural dewormers such as pumpkin seeds have not been clinically tested in dogs. There is insufficient evidence that they work; proven registered products remain necessary.
Veterinary review not yet completed
This page is awaiting review by a registered veterinary surgeon. Until then, treat the text as education based on the sources listed — not as a verified veterinary judgement.
Worms in dogs: background
Dogs can be affected by various types of worms: roundworms, tapeworms, hookworms, whipworms and lungworms. Which product is required depends on the type of parasite. Without faecal examination this is unknown — and herbal products moreover target only certain parasite species.
Registered dewormers such as fenbendazole, praziquantel, pyrantel and milbemycin are clinically tested and proven effective in dogs. For 'natural' alternatives the evidence tells a different story.
What does the evidence say per option?
Pumpkin seeds
Pumpkin seeds contain cucurbitine, a substance with antiparasitic activity in laboratory research and mouse models [1][2]. Clinical trials in dogs have not been conducted. Whether pumpkin seeds actually remove worms in dogs — and if so which species, at which life stage, at which quantity — is unknown. An adjunctive role is not excluded, but evidence is lacking.
Wormwood
Artemisia absinthium shows antiparasitic activity in cell studies, but has not been clinically investigated in dogs. With incorrect use, hepatotoxicity and neurological damage have been documented. Safety margins in dogs have not been established.
Garlic
Garlic is recommended in some circles as a dewormer. There is no evidence whatsoever of efficacy as an antiparasitic. Garlic does cause oxidative damage to red blood cells in dogs (Heinz body haemolytic anaemia), even in relatively small quantities. Garlic should always be avoided.
Deworming policy: what the guidelines say
ESCCAP, the European Scientific Counsel Companion Animal Parasites, advises risk-based deworming with registered products [3]. The frequency depends on lifestyle and exposure.
| Situation | Minimum recommendation |
|---|---|
| Average risk (household dogs) | 4× per year |
| Hunting, raw feeding, children in household | More frequently, on veterinary advice |
| Puppies and young dogs | Always via veterinary surgeon |
What does this mean in practice?
Natural products are not a replacement for registered dewormers. Several points to consider:
- Parasite type is unknown without faecal examination. Treating without diagnosis is guessing.
- Pumpkin seeds are not proven effective in dogs [1][2]. They must not replace conventional deworming.
- Garlic is toxic to dogs and should always be avoided, also as a 'preventive' product.
- Puppies must never be treated exclusively with herbal products. A severe worm infection can be fatal in young dogs.
In case of doubt about a worm infection, or with questions about the correct deworming frequency for your dog, consultation with a veterinary surgeon is the starting point.
Why this verdict?
Available research on natural dewormers is limited to laboratory studies and mouse models [1][2]. No controlled clinical trials in dogs have been conducted for any herbal option. The evidence verdict is therefore 'insufficient': efficacy in dogs has not been demonstrated.
Interactions with medication
- Wormwood (Artemisia absinthium) may increase liver toxicity when used concurrently with other hepatotoxic agents or in dogs with liver disease.
- Garlic increases the risk of haemolytic anaemia and must not be combined with medication that affects blood production.
Legal status (Netherlands)
Registered dewormers fall under the Dutch Medicines for Animals Act (Wet Diergeneesmiddelen) and are partially prescription-only. Herbal preparations for animals do not fall under this legislation and have not been assessed for efficacy or safety in dogs.
Sources
- [1] Evaluation of Anthelmintic Activity and Composition of Pumpkin (Cucurbita pepo L.) Seed Extracts — In Vitro and in Vivo Studies. International Journal of Molecular Sciences / PMC, 2016. In vitro doi:10.3390/ijms17091456
- [2] Preclinical studies of Cucurbita maxima (pumpkin seeds) a traditional intestinal antiparasitic in rural urban areas. Revista de Gastroenterología del Perú / PubMed, 2004. Narrative review source ↗
- [3] ESCCAP Guideline 01 — Worm Control in Dogs and Cats (7th edition, 2025). ESCCAP (European Scientific Counsel Companion Animal Parasites), 2025. Guideline source ↗