If only the skin of the lychee is blackened, and the flesh does not appear to be spoiled, it can still be eaten. But if the lychee skin as well as the lychee flesh are blackened, it can no longer be eaten.
If the storage time is relatively long, resulting in excessive evaporation of lychee water, so that the lychee skin blackened, but the pulp does not appear deterioration phenomenon, you can still eat. Generally eaten will not cause physical discomfort, just eat up the taste of drugs may be worse than fresh lychee.
If the lychee skin and lychee flesh are blackened phenomenon, and there is a change in flavor and deterioration phenomenon, you can not eat. Because at this time there may be more bacteria or mold in the lychee, after eating it will trigger gastrointestinal discomfort.
Daily in eating lychee, try to put lychee in the refrigerator to keep cold, so as to extend the time of lychee consumption.