Purslane is edible for humans and may be kept in vegetable or herb gardens. It also has many medicinal benefits. While purslane is nutritious to humans, it produces a toxic response in cats. This is because the plant contains soluble calcium oxalates which a cat's digestive system cannot properly break down. These calcium oxalates are released when the plant is chewed, embedding crystals into the cat's oral and esophageal tissues, which causes pain and inflammation. Once the toxins reach the digestive tract, the gut rapidly absorbs them and begins to excrete calcium oxalate crystals from the kidneys. This can lead to renal tubular necrosis, which is a life-threatening occurrence in which cells begin to die.

Purslane is a very common, fast spreading annual plant that grows as a ground covering. It goes by many names, including “Portulaca”, “wild Portulaca”, “pigwee”, “rock moss” or “moss rose”. Scientifically it is known as Portulaca oleracea of the Portulacaceae plant family. This succulent has a red stem and fleshy, spoon-shaped leaves. Small but brightly colored blossoms can be found on the plant in yellows, oranges, and fuchsias. It is very drought hardy, and often can be found growing up through cracks in driveways. Purslane generally only grows up to 10cm high, but it can spread out far distances. 

The most common symptoms from purslane consumption begin with immediate oral irritation, moving onto general gastrointestinal upset and, in severe cases, progressing to an adverse reaction in the kidneys. All signs to watch for are listed as follows:

Purslane can be found growing all over the United States. It is a hardy plant that will spring up in gardens or planters and may be found growing on the side of the road. This means that outdoor cats may likely come into contact with the plant at some point. As chewing purslane releases calcium oxalates into the mouth of the cat, most cats do not continue eating it as a painful irritation quickly develops. 

If you suspect that your cat has eaten Purslane, take it into a veterinary clinic to be professionally assessed. If you witnessed you cat eating a plant but are unsure of what it was, bring a small cutting with you so that the veterinarian can identify it. If you did not see your cat ingesting any plant materials and symptoms have now developed, the diagnostic process may take a little longer. Provide your cat's full medical history to the vet to assist in narrowing down potential causes of gastrointestinal upset. You may be asked if you allow your cat outdoors.

A complete physical examination of the cat will then be performed, measuring all of the cat's vital functions. A stethoscope may be used to listen to the cat's heart rate and breathing. The vet will also likely take the cat's temperature and measure its blood pressure. A sample of blood will then be collected via syringe so that routine testing can be done. This testing generally includes a complete blood count and a biochemical profile to get a better picture of the cat's overall condition. Urinalysis may be useful in revealing if any kidney damage has occurred.

The goal in treating purslane poisoning in a cat is to address all symptoms that have manifested and ensure the cat is in a stable condition. Generally, this will involve reducing irritation, ensuring breathing is unobstructed and doing whatever can be done to assist the kidneys.

Flushing the mouth with water will remove any remaining plant material and will also soothe the painful irritation caused by calcium oxalate consumption.

If the cat has become dehydrated, administering fluids intravenously will raise levels in the body. It will also help to flush out the kidneys and prevent toxin accumulation. Hospitalization will be required during this treatment.

Certain medications can be used to ease symptoms in the cat. Antihistamines such as diphenhydramine can help reduce inflammation and open up the cat's airways. Kapectolin can be used to sooth the stomach by creating a protective lining between the contents and the stomach walls. 

The prognosis for a cat who has consumed purslane will vary depending on how much of the plant was eaten. Most cats will not eat large amounts of purslane because of the oral pain that immediately follows chewing the leaves. This means that most cats will not consume enough of the plant for a fatal effect to occur. If the kidneys have become damaged during the incident, this damage is likely permanent. 

It may be wise to remove all Purslane from your property if you have cats. Avoid using chemicals to do so, as these are also dangerous to pets. Pulling out purslane by hand or using garden tools is an effective way to rid it from your property. Laying 3 inches of mulch in your garden can help prevent regrowth. Keeping your cat indoors is another effective way to prevent it from eating purslane.