What do brown spots on throat indicate?

Throat problem: There are many problems that can occur in the throat, so get checked. Spots of all colors can occur. A brown spot may simply represent dried mucous or prior difficulty with a nose bleed. Could be irritation from viral or bacterial infection although these are usually red or orange. You could have some non-infectious irritation from, say, post-nasal drainage (allergies) or even from reflux.