With cold and flu season arriving for some of us, Janet Sluggett, Research Fellow: Quality Use of Medicines and Pharmacy Research Centre, Sansom Institute for Health Research at University of South Australia, explains how over the counter cold and flu remedies are supposed to work and gives some guidance regarding their use:
Excellent advice: "Cough suppressants can sometimes cause drowsiness and are best avoided when coughing up mucous (a “wet” cough)" You do not want mucous pooling in your body and providing a nice, warm, moist environment in which bacteria can establish themselves. You are better off keeping your fluids up as the article advises and perhaps having steam inhalations as mentioned in the comments by both a doctor and a pharmacist.
The mention of pseudoephedrine reminds me of how 'truth in advertising' can mislead. Ages ago, before pseudoephedrine became a drug of abuse and access was tightened, I remember the packet saying "Does not cause drowsiness". That's worse than a packet of sweets which are almost 100% sugar, stating "Does not contain fat". "Do not take x hours before bedtime to ensure a good night's sleep" would have been more helpful.
While it is tempting to take over the counter products that claim to boost your immunity, I reckon my haematologist's advice that they won't work for me was good. If they do 'work', they may actually be boosting lymphocyte production, of which we have more than enough already...