The University of Auckland in New Zealand has tips on preventing the common cold, which are mostly caused by viruses. Wash your hands frequently. Alcohol disinfectants and gloves are shown to be effective as well. A daily dosage of 10-15 mg of zinc was shown to have lower rates of colds in kids. Probiotics also help prevent colds. If you do come down with the dreaded cold, antihistamines help—but not in children under five. Pain relievers can help with pain and fever and nasal sprays may help with that runny nose.