The Islamic laws pertaining to mustḥāḍa—women who have dysfunctional uterine bleeding (istiḥāḍa)—have been overlooked in the research literature. This article reopens the research discourse on this topic by discussing two related questions: may a mustḥāḍa perform religious obligations and may she have sexual intercourse? The questions are shown to be somewhat related. It is found that jurists conceded the right of a mustḥāḍa to pray but disagreed about why—implying, contrary to previous scholarship, that Islam accommodates different levels of ritual impurity—and that they held divergent views on her having intercourse. By probing and investigating Islamic legal sources, it is shown that research assertions about istiḥāḍa thus far require circumscription and re-examination.