Comprehensive evidence-based review on European antitussives.

59 Cough induced by inhalation of citric acid was reduced in adults by inhalation of menthol vapour compared with air and pine oil control 60 and in children compared with baseline challenge, but failed to reach significance when compared with placebo. 61 Surprisingly, there appears to be no published clinical studies on the effect of menthol or of the many products containing it in acute cough or bronchitis.

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Compared with placebo, there was a highly significant reduction in cough counts with the dose of 30 mg dextromethorphan.

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