Simply put, the source of TB infection is a TB patient with TB bacteria in their sputum. The main route of transmission is airborne, followed by dietary transmission and mother-to-child transmission. When a TB patient coughs, sneezes or speaks loudly, many droplets containing TB bacilli can be emitted from the lungs and airways. The more bacteria are discharged and the longer the contact time, the greater the danger. In addition, tuberculosis patients spit the sputum containing tuberculosis bacilli on the ground, and when the sputum dries and flies with the dust and is inhaled into the lungs, they will also be infected with tuberculosis bacilli, so it is advocated not to spit anywhere. Drinking sterilized or unsterilized milk, which is absorbed into the blood through the intestine, can cause tuberculosis; TB bacilli may be found on the leftover food or chopsticks used by patients with TB bacilli in their sputum, and there is also the possibility of infection if you eat the patient’s leftover food or use the patient’s unsterilized dishes and chopsticks.