Onion snot mainly refers to the liquid in the tubular leaves of green onions. I remember that when I eat green onions raw, I often remove these liquids, which makes me feel a little disgusting, strange in taste and too strong in smell. Moreover, the action of removing this liquid is very similar to "blowing my nose", plus its sticky texture, so I got the name "onion snot".
But in fact, "onion snot" can be regarded as a magical thing. Its pungent smell comes from diallyl sulfide, which may be a little dangerous if the purity is too high and the intake is too high, which may damage the respiratory tract and eyes and cause nausea and vomiting. However, the content of this substance in green onions is not high, and normal consumption is far from enough to cause harm to people, so its irritation has some relatively positive effects, such as sweating, sterilization, relieving nasal congestion and colds. In the book "Collection of Medical Prescriptions", there are also onion snot pills made with onion snot, which shows that the ancients also found its value. In fact, "onion snot" also plays a role in cooking, which can be used to remove fishy smell and relieve boredom, and it will produce special fragrance after high temperature heating. In addition to diallyl sulfide, a volatile capsaicin, onion snot also contains a variety of vitamins, pectin and other cellulose, which is similar to the mucus in okra, which helps to calm blood sugar, stimulate the secretion of digestive juice and stimulate appetite.
However, some people say that "onion snot" can nourish yin and strengthen yang, but it should be nothing. Although eating raw green onions can stimulate appetite, people will be stronger if they eat more. If they are healthy and strong, their abilities will not be bad in all aspects, so if they lean hard around such a circle, they can barely be regarded as "aphrodisiac". To sum up, it is harmless to eat "onion snot", and it has some functions such as sterilization and nasal congestion.