病名。亦名經(jīng)行或前或后、經(jīng)亂，經(jīng)水先后無定期、經(jīng)水無常、經(jīng)血不定等。指月經(jīng)來潮或提前，或錯后，經(jīng)期表現(xiàn)常不規(guī)律。多因肝郁、腎虛所致。詳肝郁經(jīng)行先后無定期、腎虛經(jīng)行先后無定期各條。