The aim of this study was to clarify the efficacy of antiepileptic drugs during a cluster of seizures in patients with convulsions with mild gastroenteritis (CwG). We retrospectively investigated the details of antiepileptic treatment in 110 consecutive episodes in 103 patients with CwG. The temporal course of the seizures and the use of antiepileptic drugs were investigated in each episode. Drugs were judged as effective when seizure cessation was achieved after administration of the drug. As the first drug, diazepam (DZP)/bromazepam (BZP) was effective in 38%, phenobarbital (PB) in 40%, and lidocaine (LD) in 100%. As the second drug, DZP/BZP was effective in 42%, PB in 69%, and LD in 100%. As the third drug, PB was effective in 70%. When the efficacy of the first doses of PB and LD were compared, the efficacy rate was significantly higher for LD than for PB (P = 0.047). In conclusion, LD was effective for the cessation of seizures in patients with CwG.