I have grayish spot on my right big toe. is that a sign for health problem?

Where is it: if it's on the toenail it could be a fungal infection. If it's on the skin it may be a skin lesion related to poor circulation or it could be cancerous in nature. You would need an evaluation and biopsy. Is the lesion irregular and rapidly growing?

A gray issue: A gray spot on the right big toe could be a number of things--it could be a blister or a spot on your toe that is rubbing on your shoe. Friction can cause discoloration of the toe pretty quickly. A more serious possibility is ischemia, meaning there is poor blood flow to the toe, which causes a (bluish) gray, dusky appearance in the beginning--usually with a lot of pain. Have it checked out!

See MD: You need to see an MD right away. It could be a fungal infection, or it could be a sign of undiagnosed diabetes