  During the study of a large set of late-type stellar X-ray sources, we
discovered a large fraction of multiple systems. In this paper we investigate
the orbital elements and kinematic properties of three new spectroscopic triple
systems as well as spectral types and astrophysical parameters (T_eff, log g,
vsin i, log N(Li)) of their components. We conducted follow-up optical
observations, both photometric and spectroscopic at high resolution, of these
systems. We used a synthetic approach and the cross-correlation method to
derive most of the stellar parameters. We estimated reliable radial velocities
and deduced the orbital elements of the inner binaries. The comparison of the
observed spectra with synthetic composite ones, obtained as the weighted sum of
three spectra of non-active reference stars, allowed us to determine the
stellar parameters for each component of these systems. We found all are only
composed of main sequence stars. These three systems are certainly stable
hierarchical triples composed of short-period inner binaries plus a tertiary
component in a long-period orbit. From their kinematics and/or Lithium content,
these systems result to be fairly young.
