Treatment of dogs with acute canine polyradiculoneuritis (ACP) is restricted to physical rehabilitation and supportive care. In humans with Guillain-Barré syndrome, the counterpart of ACP, randomized trials show that intravenous immunoglobulin (IVIg) speeds recovery. We hypothesized that dogs would tolerate IVIg well and recover faster from ACP than dogs with supportive treatment only.Sixteen client-owned dogs with ACP were treated with IVIg. Five dogs were identified by a medical record search, 11 dogs were enrolled prospectively. Fourteen client-owned dogs served as a retrospective control group. Diagnosis was confirmed using clinical features, electrodiagnostic, cerebrospinal fluid analyses and muscle/nerve biopsies. The duration of the initial progressive phase, the time from IVIg administration until dogs were ambulatory without assistance and the duration of the complete episode were evaluated and compared with the control group.Adverse reactions (anaphylaxis, mild hematuria) were observed in two dogs. Dogs treated with IVIg were ambulatory without assistance after a median of 27.5 days (range 15-127 days) from onset of clinical signs. The control group was ambulatory without assistance at a median of 75.5 days (range 5-220 days).Even though this result is not statistically significant, there is a clear trend toward faster recovery in dogs treated with IVIg.