Infrared OH lines at 1.55 - 1.56 \mu m in the H-band were obtained with the Phoenix high-resolution spectrograph at the 2.1m telescope of the Kitt Peak National Observatory for a sample of 14 metal-poor stars .

Detailed analyses of the sample stars have been carried out , deriving stellar parameters based on two methods : ( a ) spectroscopic parameters ; ( b ) IRFM effective temperatures , trigonometric gravities and metallicities from \ion Fe2 lines .
The \ion Fe1 lines present in the H-band region observed showed to be well fitted by the stellar parameters within \Delta [ Fe/H ] \leq 0.15 dex .

The oxygen abundances were derived from fits of spectrum synthesis calculations to the infrared OH lines .
CO lines in the H- and K-bands were obtained for a subsample in order to determine their carbon abundances .

Adopting the spectroscopic parameters a mean oxygen-to-iron ratio of [ O/Fe ] \approx +0.52 is obtained , whereas using the IRFM temperatures , Hipparcos gravities and [ \ion Fe2/H ] , [ O/Fe ] \approx +0.25 is found .
A mean of the two methods gives a final value of [ O/Fe ] \approx +0.4 for the metallicity range - 2.2 < [ Fe/H ] < - 1.2 of the sample metal-poor stars .