Modafinil and armodafinil work by affecting chemicals in the brain.

Alcohol affects various centers in the brain, both higher and lower order.

These drugs work in various ways to affect neurotransmitters in the brain.

B6 helps with the mood by affecting neurotransmitters in the brain.

It affects the signals in the brain that trigger cough reflex.

It is thought to work by affecting certain substances in the brain that control the sleep/wake cycle.

It works by affecting the balance of certain natural chemicals (neurotransmitters) in the brain.

There are pills that help reduce cravings by affecting chemicals in the brain.

Depression might also be affected by changes in the levels of certain chemicals in the brain, called neurotransmitters.

This makes sense physiologically, since omega-3s appear to affect neurotransmitter pathways in the brain.