We reported the case of a 74-year-old woman suffering from essential tremor for 20 years which was treated effectively with purified bovine brain gangliosides containing GM1, GD1a, GD1b and GT1b gangliosides. The trials of the treatment were conducted twice, 40 mg and 20 mg gangliosides per day respectively administered intramuscularly. Essential tremor dramatically improved with gangliosides on the second day of treatment, suggesting that the effect of gangliosides was not induced by neuronal sprouting or regeneration. It is speculated that a certain type of essential tremor is a reversible disease of membrane disorder.