Hepeel is a homeopathic remedy commonly used to treat primary and secondary functional disorders of the liver. It consists of highly diluted extracts from the following plants: Chelidonium from Chelidonium majus, L., Carduus marianus from Silybum marianum, L., Veratrum from Veratrum album L., Colocynthis from Citrullus colocynthis L., Lycopodium from Lycopodium clavatum L., Nux moschata from Myristica fragans, Houtt, and China from Cinchona pubescens, Vahl. The antioxidative, antiproliferative and biochemical effects in HepG2 hepatoblastoma cells of serial dilutions of these plant tinctures were tested, either separately or in various combinations. Upon damage of the cells with tert-butyl hydroperoxide, Carduus marianus, China and Nux moschata, in decreasing order, showed the strongest antioxidative effects. Greater than 95% inhibition of total production of malondialdehyde was reached with these three tinctures at dilutions of D4. The complete combination of the tinctures (COMB) realised in the homeopathic remedy showed an effect corresponding to the combined effects of the individual tinctures. The antiproliferative influence on the incorporation of 3H-thymidine into DNA in normal HepG2 cells was significant (p < 0.01) but relatively weak, and decreased in the order Carduus marianus, Chelidonium, Colocynthis and Veratrum. At a dilution of D4 Colocynthis showed the strongest inhibition (13.5%). The effect of the combination of Colocynthis and Veratrum was markedly higher (22.3%) than that of the individual tinctures, but was not additive. With this combination, cell numbers were reduced. COMB had similar effects on proliferation and cell numbers, with the antiproliferative effect starting at a dilution of 1:40. The conjugation of 3,4-dichloronitrobenzene with glutathione was induced only by Carduus marianus and COMB, while all other tinctures were ineffective. Neither the individual tinctures, nor COMB showed cytotoxic effects in the dilutions tested. These results demonstrate that the complete combination (COMB) realised in the homeopathic remedy and its constituents exert specific antioxidative, antiproliferative and biochemical effects on HepG2 cells which all point to a potential hepatoprotective and tumouristatic action.