頭痛に効く薬はありますか。

headache

at (place, time); in; on; during; to (direction, state); toward; into; for (purpose); because of (reason); for; with; by; from; as (i.e. in the role of); per; in; for; a (e.g. "once a month"); and; in addition to; if; although

to be effective; to show effect; to do its work; to carry out its function well; to be possible to use

medicine; pharmaceuticals; (legal) drugs; efficacious chemical (i.e. gunpowder, pesticide, etc.); (pottery) glaze; small bribe

topic marker particle; indicates contrast with another option (stated or unstated); adds emphasis

to be (usu. of inanimate objects); to exist; to live; to have; to be located; to be equipped with; to happen; to come about

indicates a question (sometimes rhetorical); or; whether or not; some- (e.g. something, someone); indicates doubt, uncertainty, etc.; emphatic prefix; suffix forming adjectives or adverbs; in that way