Sleep-related leg cramps (SRLCs) are a sleep-related movement disorder whereby painful contractions of the calf or foot muscles arise at sleep onset and during sleep and awaken the patient, interrupting sleep. Application of oral administration with Chinese herbal medicine can enhance the effectiveness and efficacy in treatment of SRLCs.This study will using Shaoyao Gancao Prescription Jiawei by adding Pueraria montana, Salvia Miltiorrhiza, into Shaoyao Gancao. The study aims to evaluate the effectiveness of a Shaoyao Gancao Prescription Jiawei in relieving leg cramps.

The study will be conducted in Yan Oi Tong Mrs Shirley W K Siu Medical Centre. All participants diagnosed with sleep-related leg cramp will be screened for eligibility criteria from the general public or referred patients via daily outpatient services. This will be a prospective trial in patients with sleep-related leg cramps (SRLCs). 30 subjects will be recruited from Yan Oi Tong Mrs Shirley W K Siu Medical Centre. The medication will be taken twice daily for 28 consecutive days. Each prescription will consist of 4 herbal granules. Study follow up will be offered every 7 days till 56th day after enrolment. Daily leg cramps log will be filled in by each individual everyday from day 0 to day 56.

Inclusion Criteria:

1. Aged 60-80
2. Complain of muscular spasm and contracture of a limb with difficulty in relaxation and movement during night time, caused by wind-cold dampness chiefly involving the sinews
3. SRLCs occur at least once in the past 7 days or twice in the past 14 days
4. Visual Analogue Scale (VAS) for leg cramp ≥ 5 (0-10) at the last attack
5. Both gender but menopause or sterilization for female subjects
6. Able to fill up the VAS for leg cramp
7. Written informed consent obtained

Exclusion Criteria:

1. Known mental disorder 2. Known serious organic disease including severe coronary function impairment, post-stroke depression and dementia, and auto-immune diseases 3. Known history of renal or liver function impairment; 4. Patients whose blood tests show exclusion criteria 5. Currently taking anticoagulant or antiplatelet 6. Any contraindications for taking herb confirmed by investigator

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