The main components of the yellow stuff inside the head of shrimp are the ovaries, pancreas and liver. As shown below:

The head of the shrimp is the place where the most toxins are absorbed and processed, and it is also the part that is most likely to accumulate pathogenic bacteria and parasites. Eating shrimp heads is basically the same as eating shrimp feces, semi-digested shrimp food, and more importantly, shrimp heads are enriched with heavy metals from the environment.

But the shrimp head does have a very tasty ingredient, that is, shrimp eggs, commonly known as "yellow". Female shrimp to maturity, the head and neck will contain shrimp yolk, so shrimp yolk shrimp must be female shrimp, but no shrimp yolk is not necessarily male shrimp, female shrimp immature shrimp can not see the yolk. The general public common crab but less recognized shrimp yolk, female shrimp in the pre-spawn shrimp head and neck containing shrimp yolk, commonly known as "red head boy.

Consumption advice is: can be eliminated as much as possible to eliminate, buy live shrimp in the water fasting in a period of time before eating.