The aim of this meta-analysis was to assess the evidence from rigorous clinical trials of the use of Crataegus spp. extract to treat patients with chronic heart failure. The authors searched the literature using Medline, EMBASE, the Cochrane Library, CINAHL, CISCOM, and AMED. Experts on and manufacturers of commercial preparations containing Crataegus extract were asked to contribute published and unpublished studies. There were no restrictions on the language of publication. Two reviewers independently performed the screening of studies, selection, validation, data extraction, and the assessment of methodological quality. To be included, studies were required to state that they were randomised, double-blind and placebo-controlled, and used Crataegus extract mono-preparations. A total of 13 trials met all inclusion criteria. In most of the studies, Crataegus spp. was used as an adjunct to conventional treatment. Eight trials including 632 patients with chronic heart failure (New York Heart Association classes I to III) provided data that were suitable for meta-analysis. For the physiological outcome of maximal workload, treatment with Crataegus spp. extract was more beneficial than placebo (weighted mean difference, 7 W; 95% CI 3–11 W; P < 0.01; n = 310 patients). The pressure–heart-rate product also showed a beneficial decrease (weighted mean difference, −20; 95% CI −32 to −8; n = 264 patients) with Crataegus treatment. Symptoms such as dyspnoea and fatigue improved significantly with Crataegus spp. treatment compared with placebo. Reported adverse events were infrequent, mild and transient; they included nausea, dizziness, and cardiac and gastrointestinal complaints.