马勃是一类担子菌门的真菌通称，一般为球形，未成熟前是白色，成熟后为褐色，内部为粉末状。可入中药，用于止血。

以前的分类法将马勃统一列为一个腹菌纲（Gasteromycetes）或腹菌亚纲（Gasteromycetidae），但最新的分类认为它们实际是一个多系群的组合，他们共同的地方是都具有一个密闭子实层的子实体，在内部产生孢子，其孢子不是像其他蘑菇一样的掷孢子，而是稳孢子，也就是说当子实体成熟时不会将孢子抛出，而是子实体爆裂开，孢子如烟雾一样散出。马勃类可能是从伞菌类逐渐进化来的，现在已经不再把它们看作是属于同一个纲的品种。

The gasteroid fungi are a group of fungi in the Basidiomycota. Species were formerly placed in the obsolete class Gasteromycetes Fr. (literally "stomach fungi"), or the equally obsolete order Gasteromycetales Rea, because they produce their spores inside their basidiocarps (fruit bodies) rather than on an outer surface. The class is artificial, however, since species—which include puffballs, earthstars, stinkhorns, and false truffles—are not closely related to each other. Because they are often studied as a group, it has been convenient to retain the informal (non-taxonomic) name of "gasteroid fungi".