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Efficacy of a Carrageenan nasal spray in patients with common cold: a randomized controlled trial

  • Martin Ludwig1,
  • Elisabeth Enzenhofer1,
  • Sven Schneider1,
  • Margit Rauch2,
  • Angelika Bodenteich3,
  • Kurt Neumann4,
  • Eva Prieschl-Grassauer3,
  • Andreas Grassauer3,
  • Thomas Lion2, 5 and
  • Christian A Mueller1Email author
Respiratory Research201314:124

Received: 1 August 2013

Accepted: 10 November 2013

Published: 13 November 2013

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Archived Comments

  1. Vitamin C tablets and zinc acetate lozenges are effective against the common cold

    5 November 2014

    Harri Hemila, Univ Helsinki

    Ludvig et al. write in their background section that vitamins and zinc are not effective against the common cold when systematically reviewed [1]. This is not correct.

    A systematic review on vitamin C and the common cold showed that vitamin C administration reduced common cold incidence by 52% (95%CI 36% to 65%) in people who were under short term heavy physical activity [2]. In addition, regular administration of 1 g/day vitamin C shortened the duration of colds in adults by 8% (95%CI 3% to 12%) and in children by 18% (95%CI 9% to 27%)[2]. Ludwig et al. specifically refer to the Karlowski et al. study that was published in 1975 [3]. Karlowski found that 6 g/day of vitamin C was twice as effective as 3 g/day, indicating dose dependency in the high dose region [3-5].

    A systematic review on zinc lozenges found 13 controlled trials [6]. There is substantial heterogeneity between the studies, but the heterogeneity was explained by the dose of zinc and the zinc salt that was used. On the basis of 3 RCT:s, high dose zinc acetate lozenges shortened the duration of colds by 42% (95%CI 35% to 48%) [6].


    1. Ludwig et al. Efficacy of a Carrageenan nasal spray in patients with common cold: a randomized controlled trial. Respir Res 2013;14:124.

    2. Hemilä H, Chalker E. Vitamin C for preventing and treating the common cold. Cochrane Database Syst Rev. 2013;CD000980.

    3. Karlowski TR, et al. Ascorbic acid for the common cold. A prophylactic and therapeutic trial. JAMA 1975;231:1038-42.

    4. Hemilä H. Vitamin C, the placebo effect, and the common cold: a case study of how preconceptions influence the analysis of results. J Clin Epidemiol 1996;49:1079-1084

    5. Hemilä H. Vitamin C supplementation and common cold symptoms: factors affecting the magnitude of the benefit. Med Hypotheses 1999;52:171-178

    6. Hemilä H. Zinc lozenges may shorten the duration of colds: a systematic review. Open Respir Med J 2011;5:51-58



    Competing interests

    No competing interests

Authors’ Affiliations

Department of Otorhinolaryngology, Medical University of Vienna, Vienna, Austria
Children’s Cancer Research Institute and LabDia Labordiagnostik, Vienna, Austria
Marinomed Biotechnologie GmbH,, Vienna, Austria
E. I. S. Executive Information Service GmbH, Vienna, Austria
Department of Pediatrics, Medical University of Vienna, Vienna, Austria