Matcha is a finely ground powder made from specially grown and processed green tea leaves. Because the entire leaf is ingested, it leads to a highly concentrated intake of all its compounds. The clear answer is that matcha is not safe or recommended for canine consumption. The high concentration of naturally occurring compounds makes even a small amount potentially dangerous for a dog.
The Primary Danger: Caffeine Toxicity
The most significant threat matcha poses to dogs comes from methylxanthines, a group of stimulants that includes caffeine and theobromine. Matcha powder is highly concentrated, containing an average of 20 to 45 milligrams of caffeine per gram. This means a typical two-gram serving can deliver up to 90 milligrams of the stimulant, a concentration far higher than standard steeped tea. This high concentration makes the risk of toxicity immediate.
Dogs are particularly sensitive because their bodies metabolize methylxanthines much slower than humans. This slow processing allows the toxins to build up, prolonging and intensifying the effects on the central nervous system and the heart. While the toxic dose is estimated around 140 milligrams per kilogram of body weight, serious clinical signs can appear at much lower levels. A small dog ingesting just a teaspoon of matcha powder could easily consume a dangerous amount of caffeine relative to its size.
Once absorbed, caffeine acts as a stimulant, blocking receptors in the brain and causing an excessive release of adrenaline. This overstimulation directly affects the cardiovascular system, leading to an elevated heart rate (tachycardia) and increased blood pressure. The combination of high concentration and slow metabolism means the effects can last for many hours, placing a prolonged strain on the dog’s major organs.
Other Risks and Digestive Issues
Beyond the acute danger of stimulant toxicity, matcha contains other compounds that can cause significant distress. The powder is rich in polyphenols, specifically catechins and tannins, which can be irritating to a dog’s digestive tract. A single two-gram serving of matcha can contain approximately 200 milligrams of catechins, a concentration that can overwhelm a dog’s sensitive stomach.
The high level of tannins is known to cause severe gastrointestinal upset, resulting in vomiting, diarrhea, and abdominal pain. These digestive issues can lead to dehydration and electrolyte imbalances, requiring veterinary intervention. In cases of chronic or very high-dose ingestion, the concentrated tannins can also stress the liver and kidneys.
Matcha also contains oxalates, naturally occurring compounds that bind with calcium. While the acute risk is low, the concentration of oxalates can be high, with some samples reporting over 17 milligrams per gram of powder. Over time, ingesting high-oxalate substances can contribute to the formation of calcium oxalate crystals and kidney stones in susceptible dogs.
Recognizing Symptoms and Emergency Steps
Symptoms of methylxanthine poisoning typically manifest within 30 minutes to two hours following ingestion. Owners should look for signs of hyperactivity, such as restlessness, pacing, and an inability to settle down. Physical symptoms include muscle tremors, an elevated heart rate, and high blood pressure. As the toxicity progresses, a dog may exhibit vomiting, diarrhea, and hyperthermia (elevated body temperature).
In severe cases, the dog may experience seizures, collapse, and abnormal heart rhythms, which can be life-threatening. If a dog has consumed any amount of matcha, it must be treated as a medical emergency requiring immediate professional attention.
The immediate step is to contact a veterinarian or an animal poison control center right away. Be prepared to provide the dog’s approximate weight and the estimated amount of matcha ingested. Treatment often involves inducing vomiting if ingestion was recent, followed by activated charcoal to absorb remaining toxins. Supportive care, including intravenous fluids and medications to control tremors or heart rate abnormalities, is necessary to stabilize the dog.