Search strategy to be used in MEDLINE (OVID) database
| Number | Search terms |
| 1 | Headache disorders [MeSH] |
| 2 | Headache[MeSH] |
| 3 | (headache or migraine or cephalgia or cephalalgia or chronic migraine):ti,ab (Word variations have been searched) |
| 4 | 1 or 2 or 3 |
| 5 | Acupuncture therapy (MeSH) |
| 6 | (acupuncture or electroacupuncture or electro-acupuncture): ti,ab |
| 7 | 5 or 6 |
| 8 | randomised:ti, ab. |
| 9 | randomized:ti,ab. |
| 10 | randomly:ti,ab. |
| 11 | placebo:ti,ab |
| 12 | Clinical trials [MeSH] |
| 13 | trial: ti,ab. |
| 14 | randomized controlled trial [MeSH]:ti,ab. |
| 15 | randomised controlled trial [MeSH]:ti,ab. |
| 16 | controlled clinical trial:ti,ab |
| 17 | 8 or 9 or 10 or 11 or 12 or 13 or 14 or 15 or 16 |
| 18 | Humans |
| 19 | 17 and 18 |
| 20 | 4 and 7 and 19 |