Umbrella tree (also known as schefflera) is a species of large flowering plant that originates in the forests of Southeast Asia and Australia. Nowadays, it is commonly grown as a houseplant because of the stark coloration of its bark and roots, though the umbrella tree is not found in many gardens outside of Southern Asia. Perhaps adding to the tree's relative lack of popularity is its highly toxic nature, which can cause most animals (including both cats and humans) to become violently ill.

Once an owner notices the symptoms of poisoning, it is important that they keep a close eye on their cat. This will help them quickly identify problems as well as have useful information for the vet when they eventually seek medical help.

There are three main chemicals present in the umbrella tree that are responsible for the symptoms detailed above: insoluble oxalates, saponins and terpenoids. Insoluble oxalates are a solidified form of oxalic acid, taking the shape of tiny sharp crystals that dig into any tissues they come into contact with, causing large amounts of inflammation and discomfort. They are responsible for the irritation of the mouth and much of the vomiting and diarrhea. Saponins are a form of naturally occurring insecticide, which work by directly binding with and attacking cells and some neuro-transmitting enzymes. This worsens the vomiting, diarrhea, and irritation, as well as causing the problems with the dilation of the pupil. Terpenoids, meanwhile, are a class of general-purpose irritants that are produced by plants in order to make them unappealing to herbivorous animals.

In order to diagnose umbrella tree poisoning, the vet will first have to perform a physical examination of the animal. This will allow them to gauge the symptoms for themselves, and test the cat's vital signs and reactions. Due to the tell-tale nature of oxalate and saponin poisoning, the vet will sometimes be able to diagnose the problem via a physical exam alone. Blood tests and laboratory analysis of the stomach contents can also be used to determine what chemicals are present in the cat's body. They will, however, usually want additional information from the owner regarding the cat's medical history and living conditions. The will also ask about the circumstances surrounding the poisoning and emergence of the symptoms in order to gain a better understanding of the situation.

If the animal is dehydrated, the vet will usually start them on intravenous fluid therapy right away. This will both alleviate the symptoms of dehydration and help them to excrete some of the toxins by producing urine. The vet will also move to get rid of the toxins present in the stomach by inducing further vomiting (which can be done by giving the cat a small amount of hydrogen peroxide). After this, the cat can be fed yogurt to dislodge the oxalate crystals. This works because it is both easy to digest, and retains enough viscosity in the stomach and bowels to exert a 'pulling' force on the crystals.

Following treatment, the vet may opt to keep the cat in the clinic for overnight observation - this will allow them to make sure that there are no further complications caused by the combined effects of the three toxins present in the umbrella tree. Following this, the owners will be left to take care of them. The vet will normally recommend that the cat is kept indoors for several days in order to build up their strength and that the owner continues the yogurt diet in order to both rest the cat's digestive system and get rid of any lingering oxalate crystals. Due to the effect that saponins can have on the nervous system, it may be necessary to return to the clinic for a follow-up visit in order to ensure the cat is recovering fully.