Male coronal groove has white foreign matter, may be the coronal groove the existence of foreskin scale, but also may be related to the foreskin glans and urethritis, urethritis and other factors. 1. Foreskin scale: men have a long foreskin, long time not to the foreskin internal cleaning, can make the coronal groove part of the presence of foreskin scale, will make the foreskin scale have white foreign body, but no discomfort symptoms. 2. Fungal glans inflammation: for example, fungal or bacterial glans inflammation, inflammatory substances increase, will make the coronal groove with white foreign matter, accompanied by glans itching, redness, tingling, itching, etc., when serious, it can cause urethritis or prostatitis and other complications. 3. Urethritis: the presence of unclean sex in men may induce nongonococcal urethritis, which will make the urethral orifice frequently appear white material, and also lead to the coronal groove area of the white foreign body, accompanied by frequent urination, burning sensation of the urethra, urethral itching, pain in urination and other symptoms. Men with white foreign matter in the coronal groove, and accompanied by other abnormal manifestations, may be the presence of disease factors, it is recommended to seek medical examination and treatment.