Study designs of evaluations included in the review
Only randomised controlled trials (RCTs) which were placebo- controlled and double-blind were included. Trials of one homeopathic potency against another, or trials of homeopathy versus other types of treatment were excluded.
Specific interventions included in the review
Homeopathic remedies and placebo. Homeopathic remedies were different in each of the four trials and ranged from a free choice of remedies to a choice of 6, 11 or 60 different remedies. Follow-up ranged from 12 weeks to 5 months.
Participants included in the review
Patients with migraine or tension headache in two of four studies was diagnosed according to International Headache Society (IHS) criteria.
Outcomes assessed in the review
Frequency, intensity, severity, duration of attacks, and use of analgesic drugs. One trial also used a neurologist's assessment.
How were decisions on the relevance of primary studies made?
The author does not state how the papers were selected for the review, or how many of the reviewers performed the selection.