"Prevention is better than cure", the statement is found to be true because:
A disease usually affects the normal body functioning but if one needs to get a cure for a particular disease, he/she needs to go for medication that has side effects on the body such as allergies.
When a person gets diseased, his body gets weak and can never recover fully.
The person with an infectious disease acts as a medium for transferring disease to a healthy person.
Thus, the prevention of a disease is always better than the steps that follow after the contraction of the disease.