A 46-year-old male patient reported difficulties in speech and swallowing following gastroenteritis. Marked open nasality (open rhinophonia) and swallowing difficulties with occasional passing of food into the nasopharynx was observed during speaking with the head held in an upright position. The patient was able to articulate clearly with the head reclined or in a lying position. Endoscopy identified complete bilateral soft palate paresis consistent with bilateral glossopharyngeal nerve palsy. Additional symptoms of cranial nerve palsy appeared in the course of the disease. Intravenous corticosteroids were ineffective. A marked improvement of symptoms was achieved after i.v. immunoglobulin therapy that was initiated following identification of serum IgM anti-GM 1 ganglioside antibodies under suspicion of cranial polyneuritis. Nasality was largely resolved under additional speech exercise therapy.