You could always try my late mother in law's cold cure. I think it helps because of the vitamin C.
In a one litre (glass NOT plastic) jug put the zest and juice of 3 oranges, 2 lemons and a lime (and any other citrus fruit you like - I like pink grapefruit in this!). Top up jug with water and add a couple of teaspoons of honey (or any sweetener you're allowed). Heat (in microwave) until hot (don't boil) - this releases the flavour from the zest. Allow to cool.
You can drink this neat or dilute it with lemonade or water. When Paul felt particularly bad one night he had a glass of this with a measure of brandy and 2 aspirin! I don't know if it helped with the cold but he didn't care!
