Table 1: Search strategy.

1exp Plant Extracts/or exp Drugs, Chinese Herbal/or exp Plants, Medicinal/or exp Medicine, Chinese Traditional/or exp China/or chinese medicine.mp. or exp Medicine, Oriental Traditional/or exp Phytotherapy/
2drugs non prescription.mp. or exp Drugs, Non-Prescription/
3medicinal herbs.mp
4herbs medicinal.mp.
5drugs non prescription.mp. or exp Drugs, Non-Prescription/
6alternative medicine.mp. or exp Complementary Therapies/
7complementary medicine.mp.
8Phytotherapy/or Plants, Medicinal/or Plant Extracts/or Herb-Drug Interactions/or herbs.mp. or Drugs, Chinese Herbal/or Plant Preparations/
9exp Phytotherapy/or exp Plants, Medicinal/or exp Plant Extracts/or exp Herb-Drug Interactions/or exp Alkaloids/or herbs.mp. or exp Drugs, Chinese Herbal/or exp Plant Preparations/
101 or 2 or 3 or 4 or 5 or 6 or 7 or 8 or 9
11randomized controlled trials.mp. or exp Randomized Controlled Trials/
12exp Random Allocation/or exp Clinical Trials/or exp Double-Blind Method/or double blind.mp. or exp Placebos/
13single blind.mp. or exp Single-Blind Method/
14clinical trials.mp.
15prospective studies.mp. or exp Prospective Studies/
16follow up studies.mp. or exp Follow-Up Studies/
1711 or 12 or 13 or 14 or 15 or 16
18exp Mental Retardation/or exp Dementia/or exp vascular dementia/or progressive brain disorder.mp. or exp Memory Disorders/
19(vascular dementia).mp.
2018 or 19
2110 and 17 and 20