Rhubarb — Food safety facts
Do not feed · Dogs · full breakdown on the linked food page
Leaves contain high levels of oxalates that can cause kidney failure; the stems are also risky in quantity. Keep rhubarb away from pets.
Short answer
No, you should never let a dog eat any part of rhubarb. Both the leaves and the stems contain high levels of oxalates that can damage the kidneys and cause severe gastrointestinal irritation. Even a small bite can lead to vomiting, abdominal pain, and potentially life‑threatening kidney failure. If your dog has ingested rhubarb, call your veterinarian or the ASPCA Animal Poison Control Center at 888-426-4435 right away.