From Cyberbotanica: These plants reach 6-18 inches in height and grow in patches. Each plant has a single stalk topped with one or two broad, deeply divided leaves that vaguely resemble umbrellas. The two-leaved plants normally produce a single, small white flower (usually in May, thus the name) from the fork in the stem. The flower develops into a pulpy, lemon-yellow berry which ripens in late summer and is the only part of the plant that isn't poisonous (however, the berries should only be eaten in moderation, if at all).
The purgative action of mayapple rhizome powder is very strong, and the compounds in it are much too toxic to attempt self-medication with this plant. The FDA rates the use of this plant as "unsafe."