The 7 Best de-Wormers for Horses

by | Jun 11, 2023 | Equine Health, Equine Treatment


For the ongoing health for your horse it is important that you work out relevant ways to keep your horse free from worms and use the best wormer available. Worms in horses are actually various parasites that infest a horse’s intestinal tract and there are a number of ways of reducing or eliminating them. Practically every horse will have some sort of infestation during its lifetime.

Get Good Advice

It is recommended that you get advice from your veterinarian or equine professional before embarking on any worming schedule. Different horses in the same environment may have quite different worm infestations. Factors that affect parasitic infestations include the age of your horse, how it is kept, pasture management, season, and where you live.


You can collect a sample of your horse’s dung to get it tested for worm burden by faecal egg counts (FEC). Spring and autumn are good times to carry out these counts. However, even without an FEC you can start an effective worming schedule.

General Types of Worm Parasites for Equines

Ascarids or Roundworms – large thick worms that can grow up to more than 30cm. The ingested larvae burrow through the horse’s small intestines into its blood system to infect the heart, liver, and lungs. From the lungs, they are coughed up and swallowed into the stomach to return to the small intestine where they develop into mature adults that in turn produce more eggs.

Older horses develop some immunity to these parasites but young stock are particularly vulnerable. Symptoms are respiratory problems, colic, and malnutrition.

Ascarids can be treated with broad-spectrum wormers like ivermectin and moxidectin however to avoid resistance, benzimidazole (BZD) and pro-benzimidazole compounds may be used too.


Bloodworms or Redworms (Large and Small Strongyles) – third-stage larvae are ingested by horses as they graze grass. The larvae migrate through the host’s small and large intestine arteries causing damage, blockages, and possibly ruptures. diarrhea, colic, and poor condition.

Large bloodworms can weaken abdominal artery walls. At some stages of the lifecycle strongyles can become encysted in the horse’s intestines so are highly resistant to chemicals. To kill these encysted parasites requires moxidectin or 5 daily doses of fenbendazole.


Threadworms – are especially dangerous for young animals that can actually become infected through the mare’s milk while suckling. The parasites then go on to live in the intestinal tract causing weakness and diarrhea. These can be controlled by drenching with Ivermectin twice a year.


Pinworms – these are not so dangerous as other parasites however, they cause irritation around the tail and anus. Your horse may start rubbing the area raw when it itches. The eggs may infest grooming items, tail wraps, stalls, and bedding so a thorough cleaning should be carried out at the same time as treatment.


Tapeworms – Horses grazing can ingest mites infested with tapeworm cysticercoids. These larvae attach themselves to the caecum and develop into tapeworms in and to feed off the horse’s food in the intestine so your horse may suffer mild colic or diarrhea. The mature tapeworms shed mature segments containing eggs. These eggs are in turn eaten by dung mites and develop into tapeworm inside the mites which are again ingested while the horse grazes.

Tapeworms can be treated with Praziquantel and Pyrantel


Bot Flies – Bots are large pesky flies active from spring through summer.  They depositing small yellow eggs that stick to a horse’s coat, especially legs and belly. If the horse ingests these eggs the larvae hatch and attaches themselves somewhere along the digestive tract. They can cause poor conditions, mild colic, ulceration, and complete blockages. Mature larvae are passed out in dung to pupate in the ground and emerge as mature flies some weeks later. An effective way to break the cycle is to remove the eggs from your horse’s hair with a bot knife. However, using a chemical wormer that kills bots at least once a year – Ivermectin and Moxidectin

Worming Products

Various products are available to remove these parasites from equines. Always follow directions of the worming product you choose to use. Follow the correct dosage. If you don’t have the means to weigh your horse you can use a calculation as an estimate –

Total girth (inches) x total girth x body length / divide 300 = approx. weight in lbs (NB This is for horses older than a year)


It might be tempting to purchase bulk lots but consider their expiry dates. Ensure maximum shelf life by storing in cool dry areas until required.


Use different products for different parasites at different times of the year. This ensures that the parasites do not build resistance or become immune to the wormer ingredients and that parasites are targeted at the right times.


It’s worth noting that, despite most parasites have part of their life cycle through pasture grazing, even stabled horses can be infected with worms. Good pasture management also decreases reinfection. If possible this management might include allowing pasture to rest from grazing at regular intervals, cross grazing with other animals like cattle or sheep, and removing horse feces on a daily basis.


DuraMectin Ivermectin Paste 1.87% Horse Wormer 1

Duramectin Ivermectin Paste Dewormer

Ivermectin Equine Paste provides effective control over a spectrum of parasites in horses

 Large Strongyles, Small Strongyles, Pinworms, Ascarids, Hairworms, Large-mouth Stomach Worms, Bots, Lungworms, Intestinal Threadworms, plus others.

It is palatable for most horses and suitable for all ages, including pregnant or lactating mares.


Pfizer Equimax Horse Wormer

With a combination of ivermectin and praziquantel, this wormer will rid your horse of most parasites including tapeworm.

It is a good one to start with if you don’t know your horse’s drench history.


Anthelcide Equine Paste

Pfizer Anthelcide EQ Equine Wormer Paste

This formulation has been developed for ease of administration.

Anthelcide EQ Paste is a paste formulation of oxibendazole, a broad-spectrum benzimidazole anthelmintic as an alternative to more frequently used.


Panacur Fenbendazole Single Dose Paste Wormer<br />

Panacur Fenbendazole Single Dose Paste Wormer

Another highly palatable paste wormer for general use to kill most parasites using fenbendazole.

This can be used for all horses including lactating or pregnant mares and can be used concurrently with trichlorfon bot treatments.



Zoetis Equine Quest Plus Gel Dewormer

A palatable gel that is easily administered to all equines for the effective control of many parasites

including bots and encysted strongyles. Great for using as a rotation of different anthelmintics so that parasites cannot build up resistance.


Panacur PowerPac Paste Dewormer

The active ingredient is fenbendazole and this pack contains a paste syringe that can treat horses with severe worm infestations

including encysted strongyles. Its unique cinnamon/apple flavor is highly palatable to most horses. It’s suitable for horses of all sizes, and ages, and conditions.


Safe-Guard Equi-Bits Dewormer Pellets

Containing fenbendazole, this is an effective option for those who do not want to use oral pastes as it comes in alfalfa-based pellet form which can be added to regular feed. 

It’s suitable for horses of all ages and sizes, including pregnant or lactating mares. It can be used regularly so can also act as a preventative against reinfection.


The above are by no means a comprehensive list of de-wormers however they are all good tried and tested products. It is now over to you to make a realistic schedule to keep your horse healthy and free of parasites.

About The Author

<a href="" target="_self">Equiniction Team</a>

Equiniction Team

We are a group of passionate riders, trainers, and horse owners who are dedicated to sharing our love and knowledge of all things equine. Whether you are a seasoned pro or just starting out on your equestrian journey, we have something for everyone. From training and care tips to the latest in equine news and events, we are your one-stop resource for all things horse-related. So come along for the ride and join our community of horse lovers today!

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