Are Hydrangeas Toxic to Cats?

by beaconpet
Why Are Hydrangeas Poisonous to Cats?

Are Hydrangeas harmful to cats? Despite their beautiful blossoms, these shrubs can pose a threat to our feline friends if consumed. Hydrangeas contain cyanogenic glycosides, a substance toxic to cats and other animals. Ingesting any part of the plant can result in symptoms like vomiting, diarrhea, and lethargy. To safeguard your cats, it’s crucial to restrict their access to hydrangeas and promptly consult a vet if you suspect ingestion. By adhering to these measures, you can guarantee your beloved pet’s safety and well-being. Learn more about cat safety and plants at Beacon pet.

Why Are Hydrangeas Poisonous to Cats?

Why Are Hydrangeas Poisonous to Cats?

Chemicals in Hydrangeas

Hydrangeas contain chemicals called cyanogenic glycosides, which can be toxic to cats and other animals, including humans. When a cat chews or ingests any part of the plant, the cyanogenic glycosides are released, which can lead to symptoms such as vomiting, diarrhea, and lethargy. Cyanogenic glycosides can release cyanide when they come into contact with specific enzymes in the digestive system. Although the level of toxicity varies based on the specific species of hydrangea and the amount ingested, it is essential to note that any amount of cyanide can be dangerous for cats.

Release of Cyanide

Cyanide is released from hydrangeas when the cyanogenic glycosides in the plant come into contact with certain enzymes in the digestive system. Cats can be exposed to cyanide if they chew or ingest any part of a hydrangea plant. Cyanide is a highly toxic substance that can interfere with cellular respiration, leading to serious health issues.

Toxicity Varies by Species

There are over 75 types of hydrangeas, and all of them contain toxins that can be harmful to cats if ingested in large quantities. While some hydrangea varieties may be more toxic than others, it is crucial to understand that any type of hydrangea can pose a risk to cats. The level of toxicity varies depending on the species, with the Bigleaf hydrangea (Hydrangea macrophylla) being the most toxic to cats. If you have hydrangeas in your home or yard, it is essential to take precautions to keep your cat safe.

Most Toxic Type of Hydrangea

The Bigleaf hydrangea (Hydrangea macrophylla) is considered the most toxic type of hydrangea for cats. This plant contains a substance that can cause vomiting, diarrhea, and lethargy if consumed in large quantities. In addition, the flowers of the Bigleaf hydrangea contain a higher concentration of the toxin compared to the leaves or stems. It is crucial to ensure that your cat does not have access to this particular type of hydrangea to prevent potential poisoning.

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Toxic Parts of Hydrangea

All parts of a hydrangea plant, including the flowers, leaves, and stems, contain cyanogenic glycosides and can be toxic to cats if ingested. However, as mentioned earlier, the flowers of the Bigleaf hydrangea are particularly dangerous due to their higher concentration of toxins. It is crucial to keep your cat away from all parts of hydrangea plants to avoid potential poisoning.

Signs of Hydrangea Poisoning in Cats

Common Symptoms

The signs of hydrangea poisoning in cats can vary depending on the amount ingested and the severity of the toxicity. Some common symptoms of poisoning include vomiting, diarrhea, loss of appetite, lethargy, weakness or depression, drooling, difficulty breathing, seizures, pale or blue gums, and rapid heart rate. If you notice any of these symptoms in your cat and suspect that they may have ingested a hydrangea plant, it is important to seek veterinary care immediately.

Are Hydrangeas Toxic to Cats?

Severity of Toxicity

The severity of hydrangea toxicity can vary depending on the amount ingested and the individual cat’s sensitivity to the toxins. While some cats may only experience mild symptoms, others may develop more severe complications. It is crucial to monitor your cat closely and seek veterinary care if you suspect they have been exposed to hydrangea toxins.

Abnormal Signs

In addition to the common symptoms mentioned earlier, there may be other abnormal signs of hydrangea poisoning in cats. These can include restlessness, tremors, weakness, confusion, abnormal heart rhythms, and even coma in severe cases. If you notice any unusual behaviors or signs of distress in your cat after potential exposure to hydrangeas, it is essential to seek immediate veterinary attention.

What To Do If Your Cat Eats a Hydrangea

Immediate Action

If you see your cat nibbling on a hydrangea plant, it is important to remove them from the area immediately to prevent further ingestion. This can help minimize the potential toxicity and prevent further complications. However, do not attempt to induce vomiting without consulting a veterinarian, as it can be dangerous to do so without professional guidance.

Contacting a Veterinarian

After removing your cat from the hydrangea plant, contact your veterinarian right away to inform them of the situation. They will be able to provide you with further instructions on what to do next based on the specific circumstances. They may recommend bringing your cat in for a thorough examination or provide guidance on monitoring for any signs of illness.

Monitoring for Illness

Following exposure to hydrangeas, it is important to closely monitor your cat for any signs of illness or abnormal behavior. If you notice symptoms such as vomiting, diarrhea, lethargy, or any other concerning signs, it is crucial to seek veterinary care immediately. Prompt treatment can help mitigate the potential effects of hydrangea poisoning.

Plant Sample for Identification

If possible, bring a sample of the hydrangea plant with you when you visit the veterinarian. This can help them identify the specific species of hydrangea and determine the best course of treatment. Proper identification will enable them to provide targeted care and support for your cat.

Are Hydrangeas Toxic to Cats?

Avoiding Induced Vomiting

Unless specifically instructed by a veterinarian, it is important to avoid attempting to induce vomiting in cats that have ingested hydrangeas or any other potentially toxic substance. Induced vomiting can be dangerous if not done under professional supervision, as it can lead to complications or aspiration.

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No Antidote

Currently, there is no specific antidote for hydrangea poisoning in cats. Treatment primarily focuses on managing the symptoms and providing supportive care. It is crucial to follow your veterinarian’s instructions carefully to ensure the best possible outcome for your cat.

Activated Charcoal and Supportive Care

Your veterinarian may recommend administering activated charcoal to help absorb any remaining toxins in the digestive system. Additionally, supportive care such as intravenous fluids and medications to manage symptoms may be necessary. Every case may differ, and the appropriate treatment plan will depend on the severity and individual needs of your cat.

How to Prevent Hydrangea Poisoning in Cats

Keeping Hydrangeas Inaccessible

To prevent hydrangea poisoning in cats, it is crucial to keep all hydrangea plants inaccessible to them. This may involve placing the plants on high shelves, using hanging baskets, or keeping them behind closed doors in rooms that are off-limits to cats. By creating physical barriers, you can minimize the risk of unintentional ingestion.

Alternative Safe Plants

Consider using alternative plants in your home or yard that are safe for cats. There are numerous cat-friendly plants available that can add beauty to your space without posing a risk to your feline companion. Research cat-safe plants and choose ones that suit your preferences while ensuring the safety of your cat.

Supervising Outdoor Time

If your cat spends time outdoors, it is crucial to supervise them closely and keep them away from any plants that may be toxic. This includes not only hydrangeas but also other potentially harmful plants. By closely monitoring your cat’s outdoor activities, you can prevent accidental ingestion and reduce the risk of poisoning.

Are Hydrangeas Toxic to Cats?

Transitioning to Indoor Environment

To provide a safe environment for your cat, consider transitioning them to an indoor lifestyle. Indoor cats are less likely to encounter toxic plants and other potential hazards. You can create a stimulating indoor environment for your cat by providing scratching posts, interactive toys, and plenty of vertical spaces to explore.

ASPCA Plant Database

The ASPCA Plant Database is a valuable resource for pet owners. It provides information on various plants and their toxicity levels, helping you identify plants that may be harmful to your cat. Familiarize yourself with this database and use it as a reference when selecting plants for your home or yard.

Emergency Contact Information

In case of an emergency, ensure that you have the contact information for your veterinarian and an emergency animal hospital readily available. This will help you take immediate action if your cat ingests a toxic plant such as a hydrangea. Having this information easily accessible can save valuable time in critical situations.

Related Topics

Toxicity in Other Plants

Hydrangeas are not the only plants that can be toxic to cats. There are numerous other plants that pose a risk to feline health if ingested. Research and familiarize yourself with common toxic plants to ensure the safety of your cat.

Snake Plants

Like hydrangeas, snake plants are toxic to cats. They contain saponins, which can cause gastrointestinal upset and other symptoms if ingested. Keep snake plants out of reach of cats to prevent potential poisoning.

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Lavender is generally considered safe for cats when used in small amounts or in products specifically formulated for feline use. However, ingesting large quantities of lavender can cause digestive upset in cats. Monitor your cat’s exposure to lavender and consult your veterinarian if you have any concerns.

Are Hydrangeas Toxic to Cats?


Mums, also known as chrysanthemums, contain compounds called pyrethrins, which can be toxic to cats. These compounds can cause symptoms such as vomiting, diarrhea, hypersalivation, and even tremors. Keep mums away from your cat to prevent potential poisoning.


Daffodils contain toxic alkaloids, primarily in their bulbs but also in the stems and leaves. Ingesting any part of a daffodil can lead to symptoms such as vomiting, diarrhea, abdominal pain, and even cardiac arrhythmias. Ensure that daffodils are kept out of your cat’s reach.

Common Garden Plants

Many common garden plants can be toxic to cats if ingested. Examples include lilies, azaleas, rhododendrons, tulips, and irises. Research the toxicity of commonly grown garden plants and take appropriate measures to keep your cat safe.

Toxic Insects

Some insects can be toxic to cats if ingested. Fireflies, certain caterpillars, and bees can cause adverse reactions and even poisoning. Be mindful of the insect activity in your area and prevent your cat from consuming insects that may be harmful.

Safe Fruits for Cats

While certain fruits can be safe for cats, others can be toxic. Avoid feeding your cat grapes, raisins, cherries, and citrus fruits, as these can cause digestive upset and other health issues. Stick to cat-friendly fruits such as small amounts of apples or bananas.

Chocolate and Cats

Chocolate contains theobromine, which is toxic to cats. Even small amounts of chocolate can cause symptoms such as vomiting, diarrhea, restlessness, increased heart rate, and even seizures. Keep all chocolate products out of your cat’s reach.


Eucalyptus is generally considered toxic to cats. Ingesting eucalyptus leaves or oil can lead to symptoms such as vomiting, diarrhea, excessive salivation, difficulty breathing, and even depression. Keep eucalyptus products away from your cat.

Lethargy in Cats

Lethargy can be a sign of various underlying health issues in cats, including poisoning. If you notice your cat being unusually tired or lacking energy, it is essential to seek veterinary attention to determine the cause and provide appropriate treatment.

Signs of Poisoning in Dogs

Dogs can also be affected by the toxins in hydrangeas and other plants. If you have both cats and dogs, it is important to be aware of the signs of poisoning in dogs as well. Look for symptoms such as vomiting, diarrhea, weakness, difficulty breathing, and abnormal behavior.

Rosemary and Cats

Rosemary is generally safe for cats when used in small amounts. However, ingesting large quantities can cause digestive upset. It is generally best to keep rosemary products away from cats to prevent potential complications.

String Ingestion in Cats

String ingestion in cats can be a serious issue that may require immediate veterinary attention. Ingesting strings or other linear objects can lead to intestinal blockages, which can be life-threatening. Keep strings and small objects out of your cat’s reach.

Spring Pet Safety Tips

Spring can bring potential hazards for pets. From toxic plants to harmful cleaning products, it is important to be aware of the safety measures to keep your cat protected during this season. Follow spring pet safety tips to ensure your cat’s well-being.

Making a Cat Throw Up

Inducing vomiting in cats should only be done under the guidance of a veterinarian. Do not attempt to make your cat throw up without professional supervision, as it can be dangerous. Contact your veterinarian for advice in case of potential ingestion of toxic substances.

In conclusion, hydrangeas can be toxic to cats due to the presence of cyanogenic glycosides, which can release cyanide when ingested. It is crucial to prevent your cat from accessing hydrangeas and other toxic plants to ensure their safety. If you suspect that your cat has ingested a hydrangea, seek veterinary care immediately. Remember to closely monitor your cat for any signs of illness and follow your veterinarian’s instructions for the best possible outcome.

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