Acetylleucine is a drug that is used for symptomatic treatment of acute vestibular vertigo and dizziness. Its pharmacodynamics are not fully understood. The hypothesis is that it restores the membrane potential, via an interaction with membrane phospholipids on the injured side of vestibular neurons mainly in the thalamus or parietal region of the cortex. Clinical trials on animals showed an improvement in locomotor balance after forced rotation or unilateral vestibular neurotomy. Acetylleucine has a marketing authorisation in France although there is no evidence of its efficacy on human. Acetylleucine neither reduced the nausea associated with this provocative stimulus, nor hastened the acquisition or retention of vestibular habituation of motion sickness and nystagmus.