Summer Dangers: Poisonous Plants and Allergies in Cats and Dogs

Summer brings with it poisonous plants and allergies, here is some advice to help your pet.

Created: 7/19/2021 Updated: 8/3/2022 - Vicky Payne

cats, dogs, Health & Wellbeing, parasite, summer advice

Poisonous plants for dogs and cats

As summer finally arrives the risk to our pets from poisonous garden plants and wildflowers increases. There are a huge number of poisonous plants and flowers, so always check the label when buying at the garden centre. Poisonous garden plants have a ‘skull and crossbones’ on the label.

Oleander is a popular choice for Mediterranean style gardens with its scented flowers. Sadly, it is highly toxic to pets and eating just one leaf could cause heart problems, seizures, and death.

Foxgloves are a classic early summer cottage garden plant, but these contain digoxin which can cause a rise in heart rate. Foxgloves can also be found in the wild, so take care on dog walks. Another popular plant containing the same poison is Lily of the Valley.

Beautiful Monkshood flowers are at their best in July and August, but all parts of the plant are poisonous to dogs and cats.

Lilies are best avoided in the garden if you have a cat as all parts are poisonous and cats can be affected from licking pollen from their fur.

Euphorbias (spurges) contain a sap which can cause skin and eye irritation and would hurt a pet’s mouth if chewed. Spurge grows wild as well as being a popular garden plant.

Many other plants and flowers are listed as being toxic; from rhododendron and hydrangea to tomatoes and all members of the onion family (including ornamental onions). Most will cause mild symptoms such as vomiting and diarrhoea.

On your dog walk watch out for deadly nightshade, water hemlock and lords and ladies, as all of these are poisonous plants. Later in the summer keep your dog away from giant hogweed. The sap of this plant is highly irritating.

If you see your pet ingesting a plant, try to interrupt them and remove any material from their mouth. Take photos of the plant so you can identify it; there are phone apps which can help with this. If you think the plant may be a poisonous plant, contact your vet immediately for advice. Washing their mouth with tepid water can be helpful to reduce further ingestion.

Beautiful white lily

What to avoid on your dog walks

Rapeseed: dangers to dogs

Oilseed Rape needs little introduction. The bright yellow plants are a common sight in the countryside in late spring and early summer. Many footpaths pass through rape fields and it is possible that this plant could cause problems for your dog.

Rape is a member of the mustard family and contains chemicals that can be irritating to the eyes and skin. There have been reports of dogs developing skin wounds from the sharp rape pods. Rape can cause allergic skin reactions and breathing problems in dogs, and rape is a common factor in human hay fever.

Eating any part of the rape plant can be irritating to the digestive system and may result in vomiting or diarrhoea.

Despite recent social media fears about rape being a killer plant for dogs, the Veterinary Poisons Information Service (VPIS) says most cases of adverse reaction to rape are mild.

Avoid any danger from oil seed rape by keeping your dog on a lead during summer walks through farmer’s fields. This will not only protect them from potential poisonous plants but also from any chemicals that may have been sprayed onto the crop. It will also prevent contamination of future food with dog faeces.

If your dog becomes ill after a summer walk, try to remember what plants you have passed as this information may help the vet treat your pet.

Dog on orange lead

Grass seeds: dangers for dogs

Grass and grass seeds present a danger to dogs and cats as summer progresses. Some types of grass have sharp awns with barbs on, which can catch in a pet’s fur. This type of grass is often called a ‘foxtail’. As the pet moves the grass seed jiggles towards the body. These sharp awns can get into the ears, between the toes, up the nose, and in through the mouth.

Grass seeds in the ears usually cause an instant reaction from the dog. The dog will shake their head, rub the ear on the ground, and may yelp in pain. You must seek veterinary help as soon as possible to prevent the seed penetrating the ear drum. Sedation is usually required to remove the seed.

Grass seeds up the nose cause acute sneezing. If the dog can’t sneeze the seed out it may cause a nosebleed, bacterial infection, or even a fungal infection. Grass seeds can be inhaled into the lungs causing severe damage. You must seek urgent veterinary help if you suspect an inhaled grass seed.

Grass seeds can push through the skin and continue to migrate. This commonly causes an abscess that may burst, heal, but then come back again. Common sites for grass seed abscesses are the feet, legs, and around the head. Grass seeds can also migrate into the body and can become lodged in the organs. Diagnosing and treating the internal abscesses they cause can be difficult and costly.

Try to avoid grass seeds causing misery for your dog by avoiding long grass in late summer. If you must cross a hayfield keep your dog on a lead and avoid running or ball games, which make inhaling a grass seed more likely. Keep the underside of hairy ears trimmed and remove the fuzzy hair from between your dog’s toes. After a summer dog walk through fields make sure you brush your dog thoroughly with a fine-toothed brush or comb to remove seeds.

Close up of dog lying down in grass

Grass also presents a danger as dogs and cats love to chew it. This can cause them to be sick, but grass can also pass through the intestines and create a hard to pass faecal mass. If your pet has grass sticking out of their bottom, use a glove or poo bag and pull it out gently and slowly. If the grass doesn’t come away easily seek veterinary help. Chewed grass can also become entrapped around the soft palate, particularly in cats, causing a coughing fit. Offering a small amount of soft food may shift the grass, otherwise removal under sedation is required.

Summer allergies in cats and dogs

Hay fever ruins the summer for many humans, but pets can also be affected by pollen allergies. In cats and dogs, pollen is more likely to cause a skin reaction than sneezing.

Dogs and cats who scratch mostly in the summer are likely to be allergic to grass and weed pollens, though there may still be some tree pollen about.

Skin allergies present as scratching, rubbing, biting, and licking. Pets may become grumpy due to a lack of sleep. These symptoms can also be seen with summer infestations of fleas, so comb through the coat and make sure you are using an effective and safe flea control product.

Ginger cat itching

Some cats and dogs will suffer from allergic rhinitis due to pollen and may sneeze, cough, or become lethargic when the pollen count is high.

Pollen is difficult to avoid but you may want to avoid dog walks when the pollen count is high, keeping doors and windows closed so less pollen enters the house, and rinsing your pet off after a walk. If you live by the sea, try a beach dog walk! Bedding should be washed more often to remove the build up of pollen, and you may want to consider a low pollen garden.

Vets can offer a range of treatments for summer pollen allergies if the pollen proves impossible to avoid.

Do you need further advice?

If you need any further advice, please contact the OSCAR Helpline Team on our freephone number 0800 195 8000 or email