I have a black foot nail. is there something wrong with me?

See a doctor: If the black toenail is new, you should have this checked. The most common benign situation is trauma to the nail, causing the nailbed to bleed and clot which appears black. However, a melanoma under the nail can also appear black. For this reason, black nails should always be evaluated by your dermatologist.

Black toenail: Injuries that cause bleeding under the nail can cause the nail to look black. There are some fungal infections which could make a nail look black also. The biggest concern is a skin cancer, like a melanoma. If there's not a known injury, get it checked by a doctor soon.

Many possibilities.: Some causes of nail discoloration include trauma due to tight shoes, infection, cancer, and medication side effects. Get the feet inspected by a professional to determine the cause of the problem, as treatment varies depending on the diagnosis.