Wet rales, like dry rales, are respiratory surges and are detected by indirect auscultation with a stethoscope. The greater the amplitude of the respiratory motion, the louder the corresponding respiratory sound, and if breathing stops, the respiratory sound does not exist. Wet rales are a type of respiratory sound, and the main mechanism of their production is the production of air bubbles by the respiratory airflow through the part of the body with liquid, which causes the bubbles to burst and the sound to occur. Therefore, in medicine, wet rales are also called blister sounds or overhydrated sounds. Depending on the size of the sound, it can be divided into small, medium and large vesicular sounds. The presence of wet rales indicates the presence of inflammatory exudate or certain lesions in the corresponding area, and is mostly seen in infectious lesions, such as bronchitis, pneumonia, tuberculosis, lung abscess, bronchiectasis, etc. Therefore, the presence of wet rales in the lungs requires identification of the specific cause and targeted treatment.