Background and Objectives: A plunging ranula represents a mucus escape reaction occuring because of the disruption of the sublingual salivary gland. It is commonly a condition of young adults, although the reported age range is 6-43 years. There is said to be a slightly female preponderance of about 1.9:1(F:M). Surgical incision has been considered the definite treatment, but sometimes complete excision is very difficult. Non-surgical treatment of these lesions has been attempted, but the results have not been satisfactory. In this study, we present our experiences with picibanil (OK-432) sclerotherapy for a plunging ranula. Materials and Methods: We retrospectively reviewed 41 patients who have undergone sclerotherapy with picibanil for plunging ranula. Information was collected on age, sex, a number of injection, post-sclerotherapy side effect and outcome of treatment. Results: 17 patients (41.5%) showed a complete response, and 20 patients (48.7%) showed inter-mediate response. No response was seen in 4 patients (9.8%). As a side effect of intracystic OK-432 injection therapy, fever (26.8%) and pain(39.0%) were observed. However, fever and pain disappeared after several days in all cases. Conclusion: The results are showing that OK-432 injection is an effective and safe treatment for plunging ranula.