ἀσκέειν, περὶ τὰ νουσήματα, δύο, ὠφελέειν, ἢ μὴ βλάπτειν → strive, with regard to diseases, for two things — to do good, or to do no harm | as to diseases, make a habit of two things — to help, or at least, to do no harm
SourceFrench (Bailly abrégé)
impf. itér. de χαίρω.
Russian (Dvoretsky)
χαίρεσκον: эп. impf. iter. к χαίρω.