The Collaborative International Dictionary of English v.0.48:

Underdose \Un"der*dose`\, n.
   A dose which is less than required; a small or insufficient
   dose.
   [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Underdose \Un`der*dose"\, v. t. & i.
   To give an underdose or underdoses to; to practice giving
   insufficient doses.
   [1913 Webster]