This study will look at the ability of ST101 to treat symptoms in subjects with Essential Tremor. This study will also examine the safety and tolerability of the drug. This study is evaluating one dose level of ST101 versus placebo in a cross-over fashion. This means that all patients will receive both ST101 and placebo, but they will receive it in a random (by chance) order.

Essential tremor (ET) is a slowly progressive, chronic neurological disorder characterized by a 4- to 12-Hertz tremor, which can involve the arms, head, voice and lower extremities. Although the hallmark of the disorder is thought to be the kinetic tremor, ET patients usually also manifest a postural tremor as well. Kinetic tremor (tremor with voluntary movements) may interfere with fine motor skills (e.g., writing, eating, drinking from a cup, pouring liquids); and depending upon its severity, may result in significant disability and diminished quality of daily living. Essential tremor represents an area of unmet medical need and this study is designed as a safety, tolerability and proof-of-concept investigation of the ability of ST101 to improve tremor. In this 2-stage study, subjects will be randomly assigned to either ST101 or placebo in Stage 1, and will receive the alternate treatment in Stage 2.

Inclusion Criteria:

• Diagnosis of definite or probable essential tremor (ET) as defined by the Tremor Investigational Group with involvement of the hands and arms of at least 2 years duration
• Tremor severity score of >/= 2 in at least one upper extremity on the Fahn-Tolosa-Marin Tremor Rating Scale
• Subject who is accessible by telephone
• Subject who can comply with study visits, study drug compliance, and study procedures.

Exclusion Criteria:

• Subject whose tremor is adequately controlled on a current treatment
• Subject who is pregnant, plans to become pregnant during the study or within 2 months of completing the study or who is presently lactating or breast-feeding
• Subject with other medical conditions that may cause or explain subject's tremor
• Subject with a recent history of hematologic/oncologic disorders
• Subject taking medication(s) that might produce tremor or interfere with the evaluation of tremor
• Subject who has had surgical intervention for their tremor in the past (e.g., ablative thalamotomy or gamma knife thalamotomy), or has had a botulinum toxin injection in the 6 months prior to screening