There are two kinds of stinky farts. One is that the stool is sparse and the fart discharged has a strong smell. When the stool is discharged, the fart will not be put. From this perspective, "Fart is the head of shit" makes sense.

Second, the fart smell is particularly strong and stinks like rotten eggs. This is due to eating too much protein food, which causes food to stay in the intestine. After the food in protein is decomposed in the digestive tract, amines are produced, and amines have this odor.