I recently
destroyed a developing cold by using vitamin D. The formula is 2,000IU for each kg. of body weight (which for me was 180,000IU a day) for 3 days. That meant 36 gel caps of 5,000IU, which seems outrageous, but it disappeared all symptoms in 48 hrs!
More info on the vitamin D cure for colds here:
Vitamin D Council | Understanding Vitamin D Cholecalciferol Health Benefits of Vitamin D