[en] Intensities of lines arising from the n = 2 and n =3 levels of high-charged, helium-like ions in very dense plasmas are calculated. The importance of recombination and cascading, and of radiation trapping, on certain line-intensity ratios is determined, and the relevance of these calculations to laser-plasma diagnostics is illustrated. Finally, the pitfalls inherent, at very high densities, in some other techniques commonly used to interpret plasma spectra, are outlined. (author)