The Collaborative International Dictionary of English v.0.48:

Ventouse \Ven"touse\, n. [F.]
   A cupping glass. [Obs.] --Chaucer.
   [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Ventouse \Ven"touse\, v. t. & i.
   To cup; to use a cupping glass. [Obs.] [Written also
   ventuse.] --Chaucer.
   [1913 Webster]