Is Hydrangea Safe for Dogs and Cats?

Hydrangeas (*Hydrangea macrophylla*) are moderately toxic to both cats and dogs. According to data from the ASPCA and the AVMA, the leaves, buds, and flowers of the hydrangea plant contain a chemical compound called hydrangein, which is a cyanogenic glycoside. When digested, cyanogenic glycosides release small amounts of hydrogen cyanide, a toxic gas that prevents cells from using oxygen. Fortunately, pets rarely eat enough hydrangea to cause severe cyanide poisoning, as the plant has a bitter taste. However, eating the leaves or buds triggers immediate gastrointestinal distress, including vomiting, diarrhea (often bloody), loss of appetite, and abdominal pain. In moderate cases, pets also show signs of lethargy, weakness, and depression. If you suspect your pet has eaten a large amount of hydrangea foliage, contact your veterinarian. To study its detailed botanical structure, see our Botanical Profile for Hydrangea. For safe, showy garden alternatives, consider planting Snapdragon or Roses. Hydrangeas are very common in residential landscaping due to their large, colorful flower heads, but they must be positioned carefully in pet-owning yards. The hydrangein toxin is present throughout the entire plant, with higher concentrations in the young buds and leaves. If a pet chews on the plant, the mechanical breakdown releases cyanide precursors, leading to nausea and abdominal pain. Veterinary treatment is generally supportive, involving fluids to maintain hydration and gastrointestinal protectants. To ensure a safe garden, plant hydrangeas behind fences or choose safe alternatives like Snapdragons.