This work presents a contrastive analysis of five Spanish lexical units (humano, individuo, persona, ser humano and sujeto) and their equivalents in portuguese. It's based on the recent studies about the general nouns and the grammaticalization processes. The analysis of different data  show a strong similarity of ser humano in both languages. On the other hand, humano is more integrated into the Spanish lexicon, hile in Portuguese indivíduo and sujeito are preferred. We also point out the high frequency and the acceptability of Pessoa and its importance in cases of indefinite or indeterminate subjects in Portuguese.