Once well into the infection even if the virus is arrested it takes time for the body to deal with the damage and that can prolong the symptoms. General procedure for treating simple viral respiratory infections includes plenty of rest and fluids, plus avoidance of immune suppressants such as sugar, found in many juices. The use of vitamin C at a dose of 1 to 6 grams per day may shorten the duration of a cold by 1 day. Vitamin A works even better and has direct antiviral effects. Take 50,000 IU per day of the emulsion and cut back when symptom-free.
Zinc lozenges have an even more profound effect.
Echinacea is used extensively in Germany for colds and is effective only if 900 mg of root extract is taken daily. Lesser doses are no more effective than placebo. Well which can eliminate a cold or flu within 36 hours. Monolaurin may be taken at the first sign of an infection as it kills the viruses rapidly. Another substance worth trying is the Amazon herb, Royal Camu.