every morning when I am about to refresh my face I spit blood, it is not red but brownish, I imagine it is blood mixed with saliva. After 2-3 spits the brownish colour disappears and I spit white as usual and I am fine during the day. What is it? it is a sign of cancer? could it be the gums or the stomach? has anyone got the same? I am 54 years old, I do not smoke, I do not drink. Thanks for answers