The locust tree (more commonly referred to as the 'black locust') is native to North America, but has been transported for growth in temperate regions across the globe. Many gardeners and landowners alike enjoy the benefits of black locust, in part due to its hardiness but mainly due to the honey-producing capacity of its distinctive white blossom. However, the tree is also remarkably toxic to humans and animals alike and if sufficient quantities are ingested, the toxins contained within can prove quite dangerous.

Black locust poisoning can often have a rapid onset, producing some fairly obvious symptoms. If these signs are observed, owners should take their pet straight to a vet, as the condition can often become life-threatening.

Vomiting: Soon after eating part of the black locust plant, the cat will start to appear nauseous (i.e. refusing food and attempting to seclude itself). This will quickly transform into gagging, retching and eventually outright vomiting. Although often written off as a fairly usual sign of food poisoning, continued vomiting can be surprisingly dangerous to the health of the cat. This is because of the large amount of liquid that can be thrown up in a short space of time, thereby exposing the animal to the risk of developing dehydration and its associated problems.

Diarrhea: Alongside the vomiting, owners may notice that their cat will lose control of its bowels, as its body attempts to further purge the black locust toxin from the digestive system. In a similar fashion to vomiting, diarrhea can cause a sudden and dramatic loss of fluid from the body. In creatures as small of cats, this can quickly result in the onset of dehydration. To avoid this, owners should make extra water available to the cat as soon as possible, ensuring that they can replenish the lost fluids in ample time.

Apathy: A somewhat distinctive sign of black locust poisoning is a change in the cat's behavior. Although digestive discomfort can lead to a degree of inactivity, owners may also notice that the cat may become unusually sedentary and seemingly unaware of its surroundings. This is often combined with a noticeable measure of weakness, as the cat starts to have trouble scaling objects and generally moving around. They may also appear apathetic to being touched or may even ignore behavior by other pets that would usually elicit a violent response.

Breathing Difficulties: Owners may also notice that their cat starts to have trouble breathing. The most obvious sign of this will be the deeper breaths and gasping noises the cat makes as it attempts to get more oxygen. This is one of the first signs that there is something seriously wrong with the animal and should prompt the owner to seek veterinary assistance.

Arrhythmia: Black locust poisoning can also have an effect on the cat's heartbeat. As the cat's condition worsens, their heart will start to beat out of time. Although not visible to the naked eye, owners can check their cat's pulse by laying their fingers flat against the rear of the animal's torso in order to feel their heartbeat. Arrhythmia may present either as a distinct uncoordinated beat of the heart, or as a 'fluttery' sensation as one ventricle beats out of time with the rest. Left untreated, this can lead to serious consequences such as bad circulation and even congestive heart failure.

Kidney Damage: One of the major consequences of black locust poisoning is its propensity to cause serious damage to the kidneys. As the organs fail, they produce some fairly distinctive symptoms, the most famous of which is yellow tinted skin and eyes caused by certain chemicals no longer being filtered out of the blood stream. Owners can additionally detect kidney damage by checking for blood in their cat's feces (which may simply turn it a much darker shade of brown).

The black locust tree contains high levels of a substance known as 'toxalbumin'. Toxalbumin is the same toxin that can be found in many venomous snakes, and in sufficient doses can prove lethal. The mechanism by which the toxin attacks the body is relatively simple. After entering the bloodstream, the toxalbumin binds with cells and disables their ability to synthesize proteins. This in turn kills the cell and hampers the ability of others to properly reproduce and regulate themselves, causing damage to major organs and producing many of the symptoms detailed beforehand. As the kidneys are a direct link between the digestive system and the bloodstream, they tend to bear the brunt of the damage from black locust poisoning. 

Once the cat has been brought to the vet, it will typically undergo a physical examination in order to directly assess the problem. The vet may also elect to draw a blood sample for laboratory analysis and could decide to use imaging techniques such as ultrasound scans in order to determine the severity of the effect that the toxins have had on the heart and lungs. The vet will also typically have a number of questions for the owner regarding the cat’s medical history as well as to do with the symptoms themselves and their rate of progression. 

Once the vet has diagnosed the problem, they will typically look to mitigate the damage that the toxalbumin can do. Their first step will normally be to pump the contents of the cat's stomach in order to remove any traces of the black locust plant that remain. This will help prevent further absorption of the toxin. Next, they will start the cat on fluid therapy, in order to directly introduce more fluids into the body. This will help flush out the toxalbumin as the cat starts to urinate, and will also stave off the effects of dehydration.

After the cat's condition has stabilized, the vet may wish to keep the cat at the clinic for further observation (if the poisoning was severe). Once returned home, owners will need to both restrict the cat's movement and keep their diet as bland as possible. This will help them properly rest both their body and their kidneys, giving them time to recover. The vet will most likely want to book a follow-up appointment in order to ensure that there has been no long-term damage sustained from the poisoning. Most cats can expect to fully return to normal in just under a couple of weeks, with the exact recovery time varying dependent on age and prior health.