Plum pits are the hard seeds found inside plums, a type of stone fruit. Each plum typically contains one pit, which is surrounded by the sweet, juicy flesh of the fruit. The pit is not edible and can be quite hard, making it necessary to remove it before consuming the fruit. These pits are part of the Rosaceae family, which also includes other fruits like cherries and peaches. While plum pits are not eaten, they can be used to grow new plum trees if planted properly. However, they contain amygdalin, which can release cyanide when metabolized, so caution is advised.