If cannabis cured colds, it would be a medical breakthrough. Doctors have been trying to figure out the "cure" for the common cold, and I assure you, cannabis isn't a cure. Just like cold medicines, it just relieves the symptoms of the cold, not curing them, but relieving the cold.

I know when I smoke and I have a cold, it loosens my throat up for a little while, but doesn't make it go away fully. It just lessens the affects of the cold for a short time.