Plantar fasciitis (say "PLAN-ter fash-ee-EYE-tus") is inflammation along the bottom of the foot and heel. It happens when the flat band of tissue (ligament) that supports the arch of your foot is inflamed or irritated.

Plantar fasciitis is the most common cause of heel pain. It is common in people who run a lot or stand on hard surfaces for long periods of time. It can happen in one foot or both feet.