inflame - become inflamed; get sore; "His throat inflamed"

sicken, come down - get sick; "She fell sick last Friday, and now she is in the hospital"

degenerate, deteriorate, devolve, drop - grow worse; "Her condition deteriorated"; "Conditions in the slums degenerated"; "The discussion devolved into a shouting match"

change state, turn - undergo a transformation or a change of position or action; "We turned from Socialism to Capitalism"; "The people turned against the President when he stole the election"

impoverish, deprive - take away

fail - get worse; "Her health is declining"

tumble - suffer a sudden downfall, overthrow, or defeat

drop away, fall away, slip, drop off - get worse; "My grades are slipping"

suffer - get worse; "His grades suffered"

lose, suffer - be set at a disadvantage; "This author really suffers in translation"

retrogress, regress, retrograde - get worse; fall back to a previous or worse condition

turn down - take a downward direction; "The economy finally turned down after a long boom"

irritate - excite to an abnormal condition, of chafe or inflame; "Aspirin irritates my stomach"

inflame - cause inflammation in; "The repetitive motion inflamed her joint"

alter, change, modify - cause to change; make different; cause a transformation; "The advent of the automobile may have altered the growth pattern of the city"; "The discussion has changed my thinking about the issue"

cheapen, degrade - lower the grade of something; reduce its worth