More than 46 million people worldwide suffer from Alzheimer's disease. A large number of potential treatments have been proposed; among these, the inhibition of the aggregation of amyloid β-peptide (Aβ), considered one of the main culprits in Alzheimer's disease. Limitations in monitoring the aggregation of Aβ in cells and tissues restrict the screening of anti-amyloid drugs to in vitro studies in most cases. We have developed a simple but powerful method to track Aβ aggregation in vivo in real-time, using bacteria as in vivo amyloid reservoir. We use the specific amyloid dye Thioflavin-S (Th-S) to stain bacterial inclusion bodies (IBs), in this case mainly formed of Aβ in amyloid conformation. Th-S binding to amyloids leads to an increment of fluorescence that can be monitored. The quantification of the Th-S fluorescence along the time allows tracking Aβ aggregation and the effect of potential anti-aggregating agents.