# Is Clover Toxic to Dogs and Cats? What to Know Is clover toxic to pets? In most cases, no. The common white clover that grows in lawns is not considered poisonous to dogs or cats, and a pet that nibbles a few leaves is usually fine. The real danger comes from moldy sweet clover, which can cause a serious bleeding disorder, and from alsike clover, which is toxic to horses. This article is educational and is not a substitute for veterinary diagnosis or treatment. ## Quick Answer - Plain white clover in your yard is not listed as toxic to dogs or cats, and small amounts are generally harmless. - Moldy sweet clover is the dangerous form. As sweet clover spoils, natural coumarins convert into dicumarol, a potent anticoagulant that can cause spontaneous bleeding [1]. - Alsike clover is documented as toxic to horses, causing sunburn, skin ulcers, and liver failure. It is not listed as toxic to dogs or cats [2]. - If your pet ate a small amount of fresh white clover and seems normal, watch them for a few hours. If they ate moldy hay, silage, or a large amount of any clover, call your veterinarian or a poison control line right away. - Never induce vomiting unless a veterinarian tells you to. ## Is Clover Toxic to Dogs and Cats? For the average pet owner standing in the backyard, the answer depends entirely on which clover your pet ate and what condition it was in. White clover (the low-growing kind with three leaflets and small white flower heads) is a common lawn plant. It is not on veterinary toxic plant lists for dogs and cats. A dog that grazes on it or a cat that chews a leaf is unlikely to have any problem. Red clover is a different plant, but it is also not a recognized pet poison. Red clover is used in some supplements and extracts, and one animal study found red clover isoflavone extract produced no notable stress responses in mice when used as a vaccine adjuvant [3]. That does not make it a food, but it does suggest red clover itself is not a major toxin for mammals. Alsike clover is the one to know about. The ASPCA lists alsike clover (Trifolium hybridum) as toxic to horses, with signs including sunburn, skin ulcers, and liver failure [2]. The toxic principle is unknown [2]. Dogs and cats are not listed as affected species, so alsike clover is not a documented pet poison, but it is not a plant you want your pet eating in quantity. Sweet clover is where the serious risk lives, and only when it is moldy. ### Which Parts and Products Matter The leaves and flowers of fresh white and red clover are the parts pets typically nibble. These are low risk. The dangerous material is spoiled sweet clover hay or silage. Any storage method that lets sweet clover mold increases the chance that toxin forms in the feed [4]. Weathered, large round bales, especially the outer portions, usually hold the highest levels of toxin [1][4]. This matters for pet owners in rural areas, on farms, or anywhere a dog can get into a hay pile, barn, or compost. A dog that chews on moldy hay is at far greater risk than a dog eating fresh clover in the lawn. Clover products also exist as supplements for people, including red clover isoflavone capsules. Keep those out of reach. A pet that eats a bottle of human supplements has ingested an unknown dose, and your veterinarian will need to calculate what that means for your pet's weight and health. ## The Toxic Principle and What It Does in the Body Fresh clover does not contain a potent anticoagulant. Moldy sweet clover does. As sweet clover spoils and becomes moldy, coumarins in the plant are converted to toxic dicumarol, also spelled dicoumarol [1]. Dicumarol is a potent vitamin K antagonist and anticoagulant [1]. Vitamin K is what the body needs to make several clotting factors. When dicumarol blocks vitamin K, the blood loses its ability to clot properly. Blood vessels that rupture during normal daily activity then keep bleeding instead of sealing. That is why the hallmark of moldy sweet clover poisoning is hemorrhage [1]. This is a chronic poisoning, not a sudden one. Animals typically have to eat moldy sweet clover repeatedly over time. If the sweet clover has a low level of toxin, an animal may eat it for months before disease appears [4]. That long timeline is why this problem is usually seen in herd animals eating the same hay supply, not in a single pet that grabbed one mouthful [4]. It is unlikely to be the cause if bleeding or slow clotting shows up in one animal from a group [4]. ## Signs and Their Typical Timeline Signs come from faulty blood clotting and blood loss from ruptured vessels [4]. Watch for: - Bleeding that will not stop from small cuts - Nosebleeds - Blood in the urine or stool - Bruising under the skin or in the mouth - Pale gums - Weakness, lethargy, or collapse - Swelling or a firm lump where blood has pooled - Difficulty breathing if bleeding occurs into the chest The time between eating toxic sweet clover and showing signs varies a great deal [4]. With low toxin levels, months can pass before disease appears [4]. With heavily moldy material, signs can come on faster. If your pet ate fresh white clover, you are unlikely to see any of this. If your pet got into moldy hay or silage, the timeline can stretch over weeks, so a normal-looking pet today does not rule out a problem. ## What to Do Right Now Stay calm and gather information. Note what plant your pet ate, how much, and when. If it was hay or silage, note whether it was moldy or weathered. Call your veterinarian, the ASPCA Animal Poison Control Center at (888) 426-4435, or Pet Poison Helpline at (855) 764-7661. These services can help you decide whether your pet needs to be seen. Do not induce vomiting unless a veterinarian tells you to. Making a pet vomit when a bleeding disorder is possible can cause harm, and it is never a do-it-yourself step. If your pet is bleeding from anywhere and it will not stop, or is weak, pale, or struggling to breathe, treat it as an emergency and go to the nearest veterinary hospital now. Bring a sample of the plant or hay with you if you can. A photo works too. Identification helps your veterinarian sort out which clover you are dealing with. For a broader look at what is and is not safe in your home and yard, see [Plants That Aren't Toxic To Cats And Dogs](/knowledge/veterinary-medicine/toxicology-and-food-safety/plants-that-aren-t-toxic-to-cats-and-dogs) and [Common Houseplants Toxic to Cats and Dogs](/knowledge/veterinary-medicine/toxicology-and-food-safety/common-houseplants-toxic-to-cats-and-dogs). ## How Veterinarians Diagnose and Treat Clover Poisoning Diagnosis starts with history. Your veterinarian will ask about access to sweet clover hay or silage over a long period, plus the signs you have seen [4]. Blood work matters here. Prolonged blood clotting times help confirm the diagnosis and guide treatment [1]. Direct confirmation of dicumarol can be hard because testing availability is limited [1]. Treatment focuses on stopping the exposure and supporting the patient. Removing the moldy sweet clover from the diet is step one [1]. Blood transfusions and vitamin K1 are the mainstays, and a response to those steps supports the diagnosis [1]. Your veterinarian will decide the vitamin K1 dose based on your pet's weight, clotting times, and overall health. There is no safe number for you to use at home. If you are worried about other plants your pet may meet, [Plants Poisonous To Dogs](/knowledge/veterinary-medicine/toxicology-and-food-safety/plants-poisonous-to-dogs) and [Plants Toxic To Cats](/knowledge/veterinary-medicine/toxicology-and-food-safety/plants-toxic-to-cats) cover the common offenders. ## Outlook After Exposure For a pet that ate a small amount of fresh white clover and is acting normally, the outlook is excellent. There is no toxin in fresh clover to treat. For moldy sweet clover poisoning, the outlook depends on how much was eaten, for how long, and how quickly treatment starts. Hemorrhage is the most common clinical sign, and it can be severe [1]. Pets that receive prompt removal from the source, transfusions when needed, and vitamin K1 often improve [1]. The best prevention is simple. The only certain method of prevention is to avoid feeding sweet clover hay or silage [4]. Low-toxin varieties of sweet clover have been developed for livestock, such as Polara, but that is a farming decision, not a pet one [4]. ## Prevention and Safer Alternatives Manage your yard with your pet in mind. - Keep fresh white clover in the lawn if you like it. It is not a pet poison. - Never let pets near moldy hay, silage, or old round bales. Store hay where animals cannot reach it. - Pull alsike clover if you find it, especially if you have horses. - Keep human red clover supplements in a closed cabinet. - Supervise outdoor time if your pet is a dedicated grazer, and redirect them to safe chew toys. - If you want to add plants, choose from [What Plants And Flowers Are Toxic To Cats](/knowledge/veterinary-medicine/toxicology-and-food-safety/what-plants-and-flowers-are-toxic-to-cats) so you know what to avoid. Plant poisoning in pets is real but less common than many owners fear. One 12-year survey of calls to a poison control center found plant exposures made up 5.7 percent of animal poisoning inquiries, with dogs involved in 61.8 percent of calls and cats in 26 percent [5]. Most of those exposures, 73.8 percent, caused only mild to moderate signs [5]. That is reassuring, but it also means the serious cases are worth taking seriously. ## Limitations and When to Contact a Veterinarian This article cannot tell you what your individual pet ate or how it will respond. Individual cases need a veterinarian who can examine your pet, run tests, and set treatment. Contact your veterinarian the same day if: - Your pet ate moldy hay, silage, or a large amount of clover - Your pet has a small cut that keeps oozing - You see bruising, nosebleeds, or blood in urine or stool - Your pet seems tired or is eating less than usual Go to an emergency hospital now if: - Bleeding will not stop - Your pet is pale, weak, or collapsing - Your pet is breathing hard or coughing blood - Your pet has a swollen, firm area that is growing Call for a routine visit if your pet has a habit of grazing and you want help pet-proofing your yard. ## Frequently Asked Questions ### Is white clover poisonous to dogs? No. White clover is not a recognized poison for dogs, and a dog that eats a few leaves in the lawn is very unlikely to get sick. The danger is moldy sweet clover, which forms an anticoagulant toxin as it spoils. ### Can cats eat clover? Cats are not known to be poisoned by fresh white or red clover. Cats rarely graze, so exposure is usually small. If your cat ate clover and seems fine, watch for vomiting or lethargy, and call your veterinarian if anything changes. ### Is red clover safe for pets? Red clover is not a listed pet toxin, and animal research on red clover isoflavone extract did not show notable stress responses in the mice studied. That does not mean it is a treat. Keep human red clover supplements away from pets, since the dose in a capsule is not meant for them. ### What if my dog ate a lot of clover? A large amount of fresh clover may cause stomach upset, but it is not a known poison. If the clover was moldy, or came from hay or silage, call your veterinarian or a poison control line right away, because that form can cause a bleeding disorder. ### Should I make my pet vomit after eating clover? No. Never induce vomiting unless a veterinarian tells you to. If a bleeding problem is possible, vomiting can make things worse, and the decision depends on what your pet ate and how they are doing. ## Related Articles - [Common Houseplants Toxic to Cats and Dogs](/knowledge/veterinary-medicine/toxicology-and-food-safety/common-houseplants-toxic-to-cats-and-dogs) - [Plants That Aren't Toxic To Cats And Dogs](/knowledge/veterinary-medicine/toxicology-and-food-safety/plants-that-aren-t-toxic-to-cats-and-dogs) - [Plants Poisonous To Dogs](/knowledge/veterinary-medicine/toxicology-and-food-safety/plants-poisonous-to-dogs) - [Plants Toxic To Cats](/knowledge/veterinary-medicine/toxicology-and-food-safety/plants-toxic-to-cats) - [What Plants And Flowers Are Toxic To Cats](/knowledge/veterinary-medicine/toxicology-and-food-safety/what-plants-and-flowers-are-toxic-to-cats) - [What Plants Can Be Toxic To Cats](/knowledge/veterinary-medicine/toxicology-and-food-safety/what-plants-can-be-toxic-to-cats) - [Is Clover Toxic to Cats? Red, White and Wild Clover](/knowledge/veterinary-medicine/toxicology-and-food-safety/clover-toxic-cats-red-white-wild) - [Is Lucky Clover Toxic to Cats? What Owners Should Know](/knowledge/veterinary-medicine/toxicology-and-food-safety/lucky-clover-toxic-cats) ## References 1. [Moldy Sweet Clover Poisoning in Animals - Toxicology](https://www.merckvetmanual.com/toxicology/moldy-sweet-clover-poisoning/moldy-sweet-clover-poisoning-in-animals). Merck Veterinary Manual. 2. [Toxic and Non-toxic Plants: Alsike Clover](https://www.aspca.org/pet-care/aspca-poison-control/toxic-and-non-toxic-plants/alsike-clover). ASPCA Animal Poison Control Center. 3. [Application of red clover isoflavone extract as an adjuvant in mice](https://pubmed.ncbi.nlm.nih.gov/32010286/). Experimental and therapeutic medicine, 2020. 4. [Sweet Clover Poisoning - Special Pet Topics](https://www.merckvetmanual.com/special-pet-topics/poisoning/sweet-clover-poisoning). Merck Veterinary Manual. 5. [Plant poisoning in domestic animals: epidemiological data from an Italian survey (2000-2011)](https://pubmed.ncbi.nlm.nih.gov/23716536/). The Veterinary record, 2013. ## Further Reading - [ASPCA Animal Poison Control Center](https://www.aspca.org/pet-care/animal-poison-control) - [ASPCA: People Foods to Avoid Feeding Your Pets](https://www.aspca.org/pet-care/aspca-poison-control/people-foods-avoid-feeding-your-pets) - [U.S. Food and Drug Administration: Potentially Dangerous Items for Your Pet](https://www.fda.gov/animal-veterinary/animal-health-literacy/potentially-dangerous-items-your-pet)