Complex combinations of botanical drugs are usually regarded as non-rational medicines. In the case of Sinupret, a combination of 5 botanical drugs, the pharmacological profile was investigated thoroughly with respect to activities on secretion of the respiratory epithelium, with respect to anti-inflammatory activities and to effects against a murine Sendai-virus infection model (including in-vitro antiviral activities), after a randomised, placebo-controlled study of the ENT-clinic of the University of Freiburg had shown superiority of the verum in patients with chronic sinusitis. For patients with acute sinusitis, the additional treatment with Sinupret improved the response rate of the patients, who were basically treated with antibiotics and nasal decongestants, significantly compared to placebo. In a series of randomised trials of the combination versus active controls, the botanical combination was shown to be at least as effective and to have a low prevalence of adverse side effects. The individual ingredients contribute to the overall pharmacological profile of the combination with secretolytic, anti-inflammatory, immunomodulating and anti-viral effects.