What does it mean when my snot is bright yellow?

Mucus: Sounds like you have a yellow mucoid discharge from your nose, otherwise known as snot. This often occurs with a viral upper respiratory infection, the common cold. This should go away in a few days. It may also be a sign of a sinus infection, if you have had sinus pain for more than 10 days. Allergies may also produce a mucoid nasal discharge.

URI: It means there's an active and likely healthy immune response to an invading or inflammatory allergen, bacteria or virus. Your immune system is doing its job. Your doctor can tell you which of the above is triggering it. Get checked!