Carry extra " Z " pacs in your bag if you have them. Vitamin C, and B, and zinc can also help fight off a cold. I also carry aciddaplis xx aciddupolis, xx Acidophilus (got that spelling correct) to help keep that good bacteria in your gut. At least this way if a bro gets sick in the field at least you can help him in the field while he's trying to work his way home. JM2c.