The eclipsing binary RZ Cas is an active semi-detached Algol system showing complex features in its light-curve and in radial velocities. Its primary minimum is a partial eclipse (Narusawa et al. 1994) and its light-curve is distorted by star spots (e.g. Varricatt et al. 1998) and possibly by non-symmetric circumstellar matter (Olson 1982). Short-period light variability with a frequency of 64 c/day was reported by several authors (e.g. Ohshima et al. 1998, Rodriguez et al. 2002).
In 2001 D.M. organized a multi-site campaign including photometric and spectroscopic observations of RZ Cas. In this paper, we report on first preliminary results obtained from the radial velocities of RZ Cas measured from time series of high-resolution echelle spectra taken at the Tautenburg 2m-telescope. These spectra allowed for a very precise determination of the binary orbit. The orbital curve very clearly shows the anomalous Schlesinger-Rossiter effect during primary minimum and, in the orbital residuals, a complex mixing of RV contributions from a large frequency range. In a first attempt we concentrate on short-term variations possibly caused by pulsations and subtract the orbital curve and all low-frequency contributions which are probably related to the time scales of orbital motion and/or rotation from the radial velocities. From the cleaned RVs we extract at least two short-period oscillations with frequencies of 56.6 and 64.2 c/d. An empirical false-alarm probability distribution computed from our data set proves the significance of the obtained variations. Both frequencies can also be found in parallel photometric observations. The second frequency dominated the oscillations in all previous observations of the star. It was observed in the brightness fluctuations of RZ Cas by Ohshima et al. (2001), Rodriguez et al. (2002), and Mkrtichian et al. (2002). During 2001, the amplitude of this oscillation decreased by an order of magnitude and is now comparable to the 56.6 c/d variation. So we conclude that the star was apparently monoperiodic and became multi-periodic in 2001.

 
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