250, 1800 and 5000 mg/kg BW orally (n=25 animals per study group). The control group received the amount of mg/kg BW excipients which were contained in the highest dosage (5000 mg/kg Bw granulate) were subjected to an eight week reversibility period after the present treatment period (IBR, 1991).

As the results of the chronic toxicity study show, the clinically chemical, histopathological as well as macroscopic organ findings as compared to the parallel controls are inconspicuous. The above mentioned study term in the experiment corresponds application in man (Schobel and Gunzel, 1984: in Eds. Kuermmertr et al., Klinsche Pharmakologie).

The mutagenicity test of Remifemin based on the Ames test, yielded no indications of a mutagenic activity of this extract. In the main test the dosage of 0.32 to 1000ug per plate were used (Scaper & Brummer, internal report, 1991)

Neither a dosage dependent doubling nor a biologically relevant increase in the mutants could be detected with and without S9 mixture (mammal liver homogenate with co-factors) as compared to the negative control. As positive controls for testing the function of the tests 9- Aminoacridine hydrochloride, Sodium azide, 4-nitro-1, 2-phenyldiamine and 2-aminoantrazene were carried along, which are known hemotoxic substances and all cause severe mutagenic effects in bacterial test systems.

As test system the breast cancer cell line MDA MB 4355 was used in cell culture. Estadiol (E2) was investigated in a concentration series from 10-4M to 10-10M.

For Remifemin in a concentration series ranging from 25 ug/ml to 0.025ug/ml was selected. Furthermore the effect of 10-6M tamoxifen or of 10-8 M E2, alone and in combination with Remifemin was tested. The growth rates were read photometrically by means of a methylene - blue stain of the tumour cells after 24-260 h incubation. For clarification of the question in-how-far the lover metabolisms of importance for the effect of Remifemin the same experiments as above were conducted with Remifemin which previously had been metabolised by rat liver extracts.

An oestrogen-induced stimulation of the proliferation of breast cancer cells was seen in E2 concentrations ranging from 10-6 M to 10-10 M. In contrast to this, E2 inhibited the rate of proliferation considerably in a concentration of 10-4 M. Remifemin showed no stimulation of the proliferation. Dosage starting with 2.5 ug/ml caused a considerable inhibition of the proliferation. The simultaneous incubation of the tumour cells with Remifemin and E2 caused an antagonism of the proliferation inhibition, while the combined application of Remifmein and Tamoxifen more severely inhibited the proliferation of the tumour cells, than the corresponding individual substances alone. A liver metabolization of the Remifemin extract in vitro had no influence on the proliferation - inhibiting effect.

Remifemin extract inhibited the proliferation of breast cancer cells. The proliferation inhibition is most likely transmitted via the oestrogen receptor. The anti-proliferative effect of Tamoxifen is boosted by Remifemin.

The constituents of the Cimicifuga extract contained in Remifemin do not stimulate the growth of the tumour cell liners in the same sense as an oestrogen influence. In the case, the elevation of the degree of proliferation of the vaginal epithelium by Remfiemin is to be interpreted as an estriol like action.

The oestrogens and their derivatives bring about different biological activities in the various target organs: estriol shows an oestrogen action primarily on the vaginal epithelium and is, as weak oestrogen, a partial antagonist to estradiol. The proliferative action of estriol on the endometrium is, in contrast, very small [32]. Due to its weak oestrogen potency, estriol possesses only a short dwelling time on the oestrogen receptor. Tissues, such as tumours, do not react or react only negligibly to estriol as they require a longer lasting binding of an oestrogen to the receptor for their proliferation.

The monograph regarding Remifemin [27] prepared by the BGA (Bundesgesundheitsamt - Federal Health Office) includes no contraindications or limitations of use in tumour patient.