The black stuff in the cat’s nostrils may be caused by boogers or nasal branches. If there is only a little black stuff, it is the black boogers formed after the secretions in the nasal cavity have dried; if there is a lot of secretions, and the cat If sneezing, runny nose, etc. occur, then it may be feline nasal congestion. It is best to take the cat to the pet hospital for examination, confirm the cause, and treat it in time to avoid aggravation of the condition.