To get a proper handle on this situation you must first understand that the common cold is a constantly mutating virus that has no ‘cure’ as such…any treatments once you have the ‘manflu’ are about symptom control and relief…i find Sudafed decongestant nasal spray excellent once the cold has taken hold, it seems to paralyse the mucous producing cells in my nose and allows me to breath and function for a few hours again.
Paracetamol and ibuprofen keep any discomfort from a fever at an acceptable level and i drink plenty of water. Touch wood my colds only seem to last a few days, i havent had a proper humdinger for a few years now.
With regard to prevention, it is all about immune support.
Go to bed earlier, take some exercise, eat a mixed diet, stay hydrated, use a multivitamin if you feel it helps…if your body (and ultimately its immune system) is in a constantly good state of readiness then your chances of succumbing to a cold are significantly reduced.
I used to get loads but then i looked at my life and realised i was eating the same foods over and over again, going to bed late (often just 5 hours sleep a night), drinking alcohol most days, exercising sporadically, drinking loads of fizzy drinks but not enough water etc etc…i changed things around last year and the results have been good enough to convince me to stick with it.