A double-blind, randomized, placebo controlled, multicenter, dose-finding phaseⅡclinical superiority study.

The trial is composed by 3 parts: 1) On-boat screening period for seasickness and safety tests will be evaluated in minus one day. 2) 4 weeks of washout period to eliminate the impact of voyage experience. 3) On-boat drug testing period. The subjects will be administered the drug before voyage. The seasickness symptoms will be evaluated during voyage. The safety test will be conducted before and after one day of on-boat testing.

Inclusion Criteria:

• Subjects fulfilling the diagnostic criteria for motion sickness
• Have medical history for motion sickness
• During screening, the severity of sea sickness is assessed as moderate or above according to sea sickness severity scale.
• Adults for 18-55 years, male or female.
• Agree to participate the study and can sign the ICF independently.

Exclusion Criteria:

• Be allergic to the study drug or be allergic constitution
• ALT, AST≥ 1.5 times of ULN, Scr>ULN, or other clinical significant lab values.
• Abnormal ECG which is clinical significant judged by investigators, including: QTc>normal range
• Have medical history for urination disorder
• Have headache, vertigo, dizziness or nsomnia caused by other diseases than motion sickness.
• Have active gastrointestinal diseases or overweight (BMI≥24kg/m2 )
• Have internal ear disease which may disturb the evaluation of motion sickness.
• Have glaucoma or posterior circulation ischemia
• Have anxiety, depression or other mental disease that investigator considering inadaptable to participate the study.
• Participated in other studies within the past 3 months.