Method for diagnosing or pre-diagnosing β-amyloidopathy Alzheimer's disease, which is associated with a cerebral deposition of protein and a reduced activity of the cerebral ABCC1 transporter, or for ascertaining the risk of a test subject suffering from such a disease, wherein the test subject already takes substances which are transported across the cerebral ABCC1 transporter, consisting of the following steps: a) determining the amount of the ingested substance in body-fluid samples from the test subject at a particular time point; b) repeating the step a) determination at at least one further, later time point; c) comparing the amounts ascertained in step a) and b) with amounts which had been defined at the same time points as characteristic of test subjects who exhibited no clinical symptoms of β-amyloidopathy Alzheimer's disease at the time of sampling, wherein the substances which are transported across the cerebral ABCC1 transporter are selected from antibiotics, virostatics / antiviral medicaments, antiallergics / antihistamines, cardiovascular medicaments, antidepressants, antihyperuricaemics, cytostatics, vitamins/vitamin analogues, antiinflammatories, antiepileptics, hormones/hormone derivatives, leukotrienes, fluorescent samples, GSH-, sulfate- or glucuronide-coupled metabolites of natural substances (endogenously produced), toxins or medicaments selected from the group consisting of 2,4-dinitrophenyl-SG, bimane-SG, N-ethylmaleimide-SG, doxorubicin-SG, thiotepa-SG, cyclophosphamide-SG, melphalan-SG, chlorambucil-SG, ethacrynic acid-SG, metolachlor-SG, atrazine-SG, sulforaphane-SG, aflatoxin B1 epoxide-SG, 4-nitroquinoline 1-oxide-SG, As 3, etoposide-Gluc, 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanol (NNAL)-3β-O-Gluc, SN-38-Gluc, 4-methylumbelliferyl-β-D-Gluc, 6-hydroxy-5,7-dimethyl-2-methylamino-4-(3-pyridylmethyl)benzothiazole sulfate (E3040S)-Gluc, leukotriene C4, prostaglandin A2-SG, 15-deoxy-Δ12,14-prostaglandin J2-SG, hydroxynonenal-SG, 17β-oestradiol-17-β-D-Gluc, glucuronosyl bilirubin, bislucuronosyl bilirubin, hyodeoxycholate-6-α-Gluc, oestrone 3-sulfate, dehydroepiandrosterone sulfate, sulfatolithocholate. a) determining the amount of the ingested substance in body-fluid samples from the test subject at a particular time point; b) repeating the step a) determination at at least one further, later time point; c) comparing the amounts ascertained in step a) and b) with amounts which had been defined at the same time points as characteristic of test subjects who exhibited no clinical symptoms of β-amyloidopathy Alzheimer's disease at the time of sampling, wherein the substances which are transported across the cerebral ABCC1 transporter are selected from antibiotics, virostatics / antiviral medicaments, antiallergics / antihistamines, cardiovascular medicaments, antidepressants, antihyperuricaemics, cytostatics, vitamins/vitamin analogues, antiinflammatories, antiepileptics, hormones/hormone derivatives, leukotrienes, fluorescent samples, GSH-, sulfate- or glucuronide-coupled metabolites of natural substances (endogenously produced), toxins or medicaments selected from the group consisting of 2,4-dinitrophenyl-SG, bimane-SG, N-ethylmaleimide-SG, doxorubicin-SG, thiotepa-SG, cyclophosphamide-SG, melphalan-SG, chlorambucil-SG, ethacrynic acid-SG, metolachlor-SG, atrazine-SG, sulforaphane-SG, aflatoxin B1 epoxide-SG, 4-nitroquinoline 1-oxide-SG, As 3, etoposide-Gluc, 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanol (NNAL)-3β-O-Gluc, SN-38-Gluc, 4-methylumbelliferyl-β-D-Gluc, 6-hydroxy-5,7-dimethyl-2-methylamino-4-(3-pyridylmethyl)benzothiazole sulfate (E3040S)-Gluc, leukotriene C4, prostaglandin A2-SG, 15-deoxy-Δ12,14-prostaglandin J2-SG, hydroxynonenal-SG, 17β-oestradiol-17-β-D-Gluc, glucuronosyl bilirubin, bislucuronosyl bilirubin, hyodeoxycholate-6-α-Gluc, oestrone 3-sulfate, dehydroepiandrosterone sulfate, sulfatolithocholate.