Several substances isolated from SCW (snail conditioned water and from snail hemolymph were tested for a possible chemiotaxic effect on Schistosoma mansoni miracidia. Two strains of miracidia were considered (SJ and BH). Agar plates prepared with one of the substances were exposed to sixty miracidia for five minutes. The number of contacts and contacts with return were counted. Ten replications were made. Eight types (and four sub types) of agar plates were prepared: normal water (control), SCW (Biomphalaria glabrata and B. tenagophila), hemolymph (B. glabrata and B. tenagophila) and amonia, calcium, magnesium, sodium and potassium. Log-linear models were fitted to the data to study the proportions of attraction to each substance and to compare them. Any possible differences in proportions of attraction between the two S. mansoni strains were tested.Foi testada a atividade miraxonal da água de condicionamento (SCW) e da hemolinfa de Biomphalaria glabrata e de B. tenagophila frente a miracídios de Schistosoma mansoni das linhagens BH e SJ. Foram pesquisados e isolados alguns componentes de SCW. Com os componentes isolados de SCW e com a hemolinfa foram preparados blocos de ágar. Esses blocos, assim preparados, foram colocados frente a miracídios de S. mansoni para avaliação da atividade miraxonal. Foram detectadas diferenças entre a ação miraxonal da hemolinfa e das substâncias isoladas de SCW. Observaram-se diferenças significativas entre os efeitos miraxonais das duas espécies de moluscos pesquisados frente a miracídios das linhagens BH e SJ.154170