  Symbiotic stars are the long period, binary systems of strongly interacting
stars at the final stages of evolution which can be useful tool to understand
the chemical evolution of the Galaxy and the formation of stellar populations.
Knowledge of the chemical composition of the symbiotic giants is essential to
advancing our understanding of these issues but unfortunately reliably
determinations exist only in a few cases. We perform a program for detailed
chemical composition analysis in over 30 symbiotic giants, based on the high
resolution, near-IR spectra, obtained with Phoenix/Gemini South spectrometer.
The methods of the standard LTE analysis is used to obtain photospheric
abundances of CNO and elements around iron peak. Here we present results
obtained for four objects: RW Hya, SY Mus, BX Mon, and AE Ara. Our analysis
revealed a significantly sub-solar metallicity (Me/H ~ -0.75) for RW Hya, a
slightly sub-solar metallicities (Me/H ~ 0.2-0.3) in BX Mon and AE Ara, and a
near-solar metallicity in SY Mus. 12C/13C isotopic ratios are low in all cases,
ranging from ~6 to ~10, and indicate that the giants have experienced the first
dredge-up.
