also: しゃかやく
The doctor prescribed a strong purgative.
Specifically a medicine for constipation; 瀉下薬 is a broader term that includes stronger purgatives used for bowel cleansing.
Standard kanji spelling for this medical term. The reading しゃげやく is the most common pronunciation.
Alternate reading; less common than しゃげやく.
From 瀉下 (しゃげ, purgation) + 薬 (やく, medicine). The kanji 瀉 means 'to pour out' or 'to drain', and 下 means 'down', together referring to the purgative effect.