Affecting more than half of menstruating women, dysmenorrhea is a cramp which causes abdominal or
lower back pain just before or during a menstruation. In western medicine, non-steroidal antiinflammatory
drugs (NSAIDs) are normally used to treat primary dysmenorrheal symptoms. Despite their
rapidity in relieving pain, NSAIDs have many serious side effects on the liver, kidney, and
gastrointestinal tract. Thai traditional medicines comprise many preparations for treating dysmenorrhea,
especially Prasaplai preparation which has been listed in the Thai traditional common household drug list
since 2006. The use of Prasaplai was originated about 100 years ago and is still being used in the present
time to treat dysmenorrhea. This review focuses on the history of the preparation, active ingredients, and
biological activities especially on cyclooxygenase inhibitor, artifacts occurred in the preparation,
quantitative analysis, and clinical trial of Prasaplai formulation.