1. We conducted an overview and quantitative meta-analysis of all experimental literature on the protective effects of serial agitated dilutions (SADs) of toxin preparations. 2. Articles were systematically collected and evaluated for scientific quality using pre-defined methodological criteria and then independently analysed for validity. 3. We found 105 publications exploring the effects of SAD preparations in toxicological systems. 4. The quality of evidence in these studies was low with only 43% achieving one half of the maximum possible quality score and only 31% reported in a fashion that permitted reevaluation of the data. 5. Very few studies were independently replicated using comparable models. 6. Among the high quality studies, positive effects were reported 50% more often than negative effects. 7. Four of 5 outcomes meeting quality and comparability criteria for meta-analysis showed positive effects from SAD preparations. 8. Average percent protection over controls in these preparations was 19.7 (95%Cl 6.2-33.2). 9. Further research with special attention to methodological detail and independent replication should be done.