Many people’s lives are affected by various protein misfolding diseases. Since these diseases are currently not curable, their prevention is very important. Fruit, including black chokeberries, contain effective fibril formation inhibitors and are recommended for consumption. We investigated the anti-amyloidogenic effect of black chokeberry juice using turbidity measurements, aggregation kinetics assay and Congo red binding experiments. We found, that black chokeberry juice was very effective in inhibiting α-chymotrypsin amyloid-like fibril formation in aqueous ethanol in a concentration dependent manner, since its total polyphenol content is much higher than that of most other fruit. Due to the intense blue color of the juice, it can be used as a natural food coloring, which has also a health-promoting property.