Mangosteen itself will secrete yellow substances, which may be caused by injuries encountered during picking or transportation. It is also possible that the fruit is not fully ripe with yellow pulp, which can be eaten, but it will be astringent. Another possibility is that it has been stored for too long, it is not fresh, and the pulp is going bad and inedible. First, the damaged mangosteen itself will secrete yellow substances, probably because the fruit is squeezed during picking or transportation, which will break the skin, resulting in the secretion of yellow substances. You can rest assured that it will not be harmful to the human body, but exposing the broken skin for too long will definitely affect the freshness and taste. Second, the mangosteen that is not ripe and not fully mature will also have yellow pulp, which is not harmful and can be eaten, but the taste is definitely not as good as that of the ripe one, and it will be very astringent. You can look at the peel when choosing, and the purple and black ones will be ripe. Third, there is another possibility that the stale yellow pulp has been left for too long, which may cause the pulp to deteriorate and not fresh enough. It will be bitter to eat. If it tastes bitter, don't eat it.