The rule of thumb I found for vitamin C (sodium ascorbate) is 250mg/kg body weight for people when they're sick/might be getting sick.<br><br>
I think in pounds, so that works out to be 1.1g/day per 10-pounds of body weight, spread out over the day as much as possible. But it's just a starting point, I think it can be somewhat higher or lower depending on the individual.<br><br>
I do this for the whole family, really seems to help.<br><br>
No idea about echinacea, I don't know how to use it.