A fishy smell may be caused by bacterial vaginitis if you are a woman. The leukorrhea will smell fishy, sometimes the smell is stronger and will be emitted from the inside out. Women will smell fishy when they have their period, usually the fishy smell will be lighter and will not appear foul. Some people are secreted urine, sweat, breath, will have a relatively strong fishy smell, which may be caused by the relatively rare trimethylaminuria metabolic defect. Trimethylaminuria is a congenital metabolic defect, after birth, because the body is not able to metabolize trimethylamine, so the body fluids secreted will smell fishy. Often on the body will smell a relatively strong fishy smell, you can go to the hospital to check the cause, and then use drugs for treatment.