We wish to thank Drs A Alario, T Klassen, L Landau, D Lines, S Schuh and P Schweich for providing unpublished data from their studies. We are also grateful to Mr Derek Stephens and Ms Terri Myhr, of Toronto for their assistance with the statistical analyses performed for the original review. The original review was presented in part at the annual meeting of the Ambulatory Pediatric Association: May 1994, Seattle, Washington.

We would like to acknowledge the contributions of three of the original co‐authors, JD Kellner, A Ohlsson and EEL Wang in conducting the original work for this review on which this update is based (Kellner 1998). Drs F Gurkan, B Karadag and H Patel generously provided unpublished data from their studies for the 2006 update. Drs. Tinsa and S Ralston graciously provided unpublished data from their studies for the 2010 update. The assistance of Sarah Thorning in conducting the searches for the update is also appreciated.

Taixiang Wu provided invaluable assistance in assessing eligibility of trials published in the Chinese language. The support of the National Prescribing Service (NPS), Australia allowed A Bhasale to contribute to this update and is appreciated. Reviews were received with thanks from the following peer referees: Alison Thomas, Craig Mellis, Rob Ware, Juan Lozano, Amanda Young, David Isaacs, Nelcy Rodriguez‐Malagon, and Inge Axelsson. Finally we would like to acknowledge with thanks the support and guidance of Liz Dooley, Managing Editor for the Cochrane ARI Group, throughout the 2006 and 2010 updates.