The Collaborative International Dictionary of English v.0.48:

Physic \Phys"ic\ (f[i^]z"[i^]k), v. t. [imp. & p. p. Physiced
   (f[i^]z"[i^]kt); p. pr. & vb. n. Physicking
   (f[i^]z"[i^]k*[i^]ng).]
   1. To treat with physic or medicine; to administer medicine
      to, esp. a cathartic; to operate on as a cathartic; to
      purge.
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   2. To work on as a remedy; to heal; to cure.
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            The labor we delight in physics pain. --Shak.
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            A mind diseased no remedy can physic. --Byron.
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The Collaborative International Dictionary of English v.0.48:

Physic \Phys"ic\ (f[i^]z"[i^]k), n. [OE. phisike, fisike, OF.
   phisique, F. physique knowledge of nature, physics, L.
   physica, physice, fr. Gr. fysikh`, fr. fysiko`s natural, from
   fy`sis nature, fr. fy`ein to produce, grow, akin to E. be.
   See Be, and cf. Physics, Physique.]
   1. The art of healing diseases; the science of medicine; the
      theory or practice of medicine; -- an archaic term,
      superseded by medicine. [archaic] "A doctor of physik."
      --Chaucer.
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   2. A specific internal application for the cure or relief of
      sickness; a remedy for disease; a medicine.
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   3. Specifically, a medicine that purges; a cathartic.
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   4. A physician. [R.] --Shak.
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   Physic nut (Bot.), a small tropical American euphorbiaceous
      tree (Jatropha Curcas), and its seeds, which are well
      flavored, but contain a drastic oil which renders them
      dangerous if eaten in large quantities.
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WordNet (r) 3.0 (2006):

physic
    n 1: a purging medicine; stimulates evacuation of the bowels
         [syn: purgative, cathartic, physic, aperient]