Hi The correct verb is prevent for example : It has been claimed that fibre in the diet could help prevent many serious diseases. let to see where we use avoid : In situations you don't like a specific thing or an action and also when something may harm you, you can use avoid. for example : I avoid making friendships with a smoking guy! You should avoid drinking alcohol Google defines the words as : Avoid: keep away from or stop oneself from doing (something). Prevent: keep (something) from happening.