Hello nanee seaside,
I'm sorry, your question is not specific enough to answer fully because depending on what arteries are diseased and what you mean by diseased in the first place, the treatment differs.
However, generally speaking, arteries become "diseased" from 3-4 common health problems. First, smoking wreaks havoc on blood vessels. So, if you you smoke and have bad arteries, stop smoking. Also, high blood pressure can cause hardening of the arteries. There are many different blood pressure medications for high blood pressure. Next high cholesterol can also cause arterial disease, so lowering your cholesterol level through drugs and lifestyle modifications can help. Diabetes can harm your arteries, so controling blood sugar is important for maintaining artery health.
This list is by no mean inclusive of all the diseases that can cause artery problems!
And if this sounds complicated, IT IS! All of these diseases should be recognised, monitored, and treated by your doctor.
To your health,
Neil MD