Mike's dad, a champion veterinarian, always said "a cold lasts ten days - not matter what." I hated hearing this because I always wanted to think that I could do some magic thing to make it shorter, but I think he was right. But see for yourself. Next time you get a cold, start counting.
As a general rule and when possible, Mother Rabbit does not believe in taking over-the-counter medicines because for every benefit there are side effects to deal with. In most cases I think that the side effects of most cold medicines are worse than the cold symptoms themselves. I like to gut out a cold as long as possible... (But you know the ugly symptoms that make it impossible to be in contact with other humans: nose resembles a faucet turned on, sneezing that looks like a tissue commercial, tears running down your face without reason.)
When Mother Rabbit has to turn to cold medicine, her choice is TheraFlu. You pour the flavorful contents into almost boiling water and you have the impression are are drinking a soothing cup of hot tea. I add lemon for effect. It is already sweet or I would add honey too. It comes in a day version (which won't make you drowsy) and a night version (which won't keep you awake.)
And don't forget homemade chicken soup. The fat in the broth really does provide soothing comfort to a sore throat. And drink lots of fluids. And get extra sleep. And then maybe your cold will last only nine days.