Iatrophobia- Fear of going to the doctor or of doctors.
Ichthyophobia- Fear of fish.
Ideophobia- Fear of ideas.
Illyngophobia- Fear of vertigo or feeling dizzy when looking down.
Iophobia- Fear of poison.
Insectophobia - Fear of insects.
Isolophobia- Fear of solitude, being alone.
Isopterophobia- Fear of termites, insects that eat wood.
Ithyphallophobia- Fear of seeing, thinking about or having an erect penis