Asthma can be prevented by some natural ways. One of the most effective ones is to drink coffee. In fact, black coffee contains caffeine that helps both treat and prevent asthma. All you need to do is trying to consume from 1 to 2 cups of coffee per day.
Another help can be drinking some ginger tea as well as eating fish such as una, salmon and sardine.
Source: Home Remedies for Asthma - Authority Remedies