Ground apple is more commonly known as 'chamomile' and is not to be confused with the 'Peruvian ground apple'. Chamomile is a wildflower that grows in temperate climates and is most commonly found across Europe. Whilst it is not typically favored by gardeners owing to the small size of its flowers, the plant has found favor with those looking to exploit its medicinal properties for use on humans. However, the chemicals found within chamomile can be extremely toxic to a variety of animals, including all species of cats.

In extremely small doses, the chemicals found in chamomile can sometimes be administered to cats in order to treat health conditions. If the raw unprocessed plant is ingested, however, the concentration of these toxins can cause serious health problems. It is important that owners note the order in which the symptoms appear and their rate of progression, as this can help later when a veterinary professional is attempting to diagnose the problem.

After consuming the chamomile plant material, the cat will typically begin to exhibit signs of nausea and indigestion. This will become visible to the animal's owners as it rejects food, isolates itself and becomes sensitive to being touched, perhaps even reacting violently. After a short while, the cat will begin to vomit as its body attempts to expel the chamomile substances from the digestive system. Although seemingly a minor symptom, vomiting can lead to more serious consequences as the cat begins to lose copious amounts of fluids. In conjunction with the other symptoms, vomiting can lead to dehydration. To prevent this, owners should make additional water available for the cat to drink as the illness continues.

In a further attempt to get the ground apple out of its system, the cat will also start to lose control over its bowels. Although an effective measure that will help empty out the contents of the digestive tract, diarrhea causes the cat to lose a large quantity of liquid in a very short space of time. In an animal as small as a cat, this can quickly lead to serious levels of dehydration, especially when it has already been losing fluids because of vomiting. For this reason, owners should keep a close eye on their pet for signs of dehydration and seek medical attention if they manifest. As with vomiting, it is also advisable to make extra fluids available for the cat to drink, as this will help immensely with keeping them properly hydrated.

A slightly more specific sign of chamomile poisoning is irritation of the mouth. Owners will typically first notice this taking the form of excess salivation, as the cat tries to flush the toxins from its mouth. This can either look like simple drooling or it can make the cat appear as if it is foaming at the mouth. Obviously, this continued drooling can be a minor cause of fluid loss, so owners should keep a lookout for the signs of dehydration. The irritation will also cause swelling and redness on the nose and lips of varying severity depending on the amount of chamomile that has been consumed. The cat might also rub its face with its paws in an attempt to rub the irritants away.

Touching the ground apple plant can also cause a rash to break out at the site of contact. This will normally cause a patch of red, itchy skin to appear and can only be positively identified via direct inspection of the cat's skin. The animal may also start to scratch the affected area repeatedly, giving a clue as to the duration and degree of the irritation.

The ingredients of the ground apple plant that are sought for their medicinal properties are the same chemicals that cause many of the symptoms of the poisoning. The chemicals are known as 'essential oils'. Essential oils are often used for their pain relieving and hypoallergenic properties caused (in short) by their interruption of normal cell function. Whilst in humans the effects are relatively benign, cats can have an extremely negative reaction to them. It is this disruption of the normal processes of the body that causes the vomiting and diarrhea, both as a consequence of metabolizing the oils and as an attempt to purge them from the body. Fortunately, however, the chemicals present in the ground apple are not lethal or permanently debilitating in their effects, unlike some other varieties of essential oils. Tannic acids are also present in large quantities and are responsible for much of the irritation of the mouth and face. These acids also cause nausea and stomach upset and can provide the first clues that there is something wrong.

Upon meeting the cat, the vet will first perform an examination by hand in order to establish the severity of the symptoms and identify any areas on the body that have been particularly badly affected. This will also help to rule out other health problems from the diagnosis. Additionally, the vet may wish to perform an imaging scan using ultrasound or an endoscopy in order to establish the state of the digestive tract before treatment begins. The vet will also have a battery of questions for the owner regarding both the symptoms and their progression as well as the cat's medical history and living arrangements. Having some information prepared before attending the appointment will help immensely with speeding up the diagnosis.

The most usual choice of treatment will be to start the cat on fluid therapy. This will intravenously administer liquids into the cat's bloodstream to both alleviate the effects of dehydration and provoke urination, thereby 'flushing' the metabolized toxins from the body. It may also be necessary to absorb the residual toxins lingering in the stomach with a dose of activated charcoal, thereby preventing the symptoms from reappearing.

After receiving treatment for chamomile poisoning, most cats will not require follow-up visits unless they have developed some sort of secondary condition (i.e. dehydration). Recovery times can vary depending on the amount of the plant that has been ingested, but the majority of animals will be back to normal after several day (with older animals requiring slightly longer to get better). Owners will, however, have to restrict the cat's diet to bland foods only for a while in order to prevent further stomach upset. If the cat has been particularly badly affected, it may be necessary to restrict their activity to the house, thereby conserving their energy for the recovery process.