Obsolete medical term for diarrhea. In modern Japanese, 下痢 (げり) is used instead.
The term 瀉痢 is often seen in medical texts from the Edo period.
From Chinese 瀉痢 (xièlì), a compound of 瀉 'to pour out, to have diarrhea' and 痢 'dysentery, diarrhea'. The exact historical derivation is uncertain; the spelling is conventionally associated with the meaning.