Pentoxifylline (PTX) was proved to exert both anti-inflammatory and anti-fibrotic effects, and was used therapeutically in this experimental model to investigate its role alone or with praziquantel (PZQ) in Schistosoma mansoni-infected mice, and to explore its impact on the tissue expression of transforming growth factor-beta1 (TGF-beta1). S. mansoni-infected mice were divided into seven groups: Control untreated (I), treated with curative dose of PZQ, 500 mg/kg/day for 2 consecutive days (II), or subcurative dose, 100 mg/kg/day for 2 consecutive days (III), treated with PTX (10 mg/kg/day for 5 days/wk) alone for 4 weeks (IV) or in addition to subcurative dose of PZQ (V), and treated with PTX alone for 8 weeks (VI) or in addition to subcurative dose of PZQ (VII). All animals were killed 10 weeks post infection. Parasitological assessment of worm burden, tissue egg load and oogram pattern was carried out. The degree of granulomatous fibrosis and eosinophilic cell population was quantified in Sirius-red-stained sections and tissue transforming growth factor beta-1 expression was estimated immunohistochemically. Serum ALAT and GGT, as well as hepatic content of reduced GSH, were measured. The results revealed the highest percent of worm reduction and dead ova in groups (II) and (VII) accompanied by significant diminution in granulomatous parameters, collagen content and TGF-beta1 tissue expression. Moreover, treatments with PTX and/or PZQ ameliorated the liver functions. In conclusion, prolonged treatment with PTX has a potent anti-fibrogenic role especially when used in the early stages of infection, with limited toxic effects on schistosome worms and eggs. Thus, PTX can be used as an adjuvant therapeutic tool with anti-helminthic drugs in the treatment of human schistosomiasis.