A method of manufacturing a medical antimicrobial suture having a grapefruit extract which is a grapefruit seed extract including naringin, ascorbic acid or citral is provided. The method includes preparing grapefruit extract solution with a concentration of 500 to 2000 ppm by mixing the grapefruit extract with methanol solvent and impregnating a biodegradable monofilament suture with the grapefruit extract solution for more than 360 minutes. The grapefruit extract is continuously released in a body for 70 hours after the antimicrobial suture is inserted into the body.
