Escherichia coli is naturally present at the gastrointestinal tract of humans, but is also involved in diseases such as urinary tract infection. The current scenario of bacterial resistance to antimicrobials raises the demand for new drugs, and natural products represent interesting sources of bioactive compounds. Here we investigated the cytotoxicity and antimicrobial potential of 80% methanolic extracts of Spondias tuberosa (umbu), Spondias purpurea (seriguela), and Theobroma grandiflorum (cupuaçu) fruit juice pulps against clinical isolates of uropathogenic E. coli. Phytochemical aspects of the pulps were elucidated, and their antioxidant properties were analyzed. The minimal inhibitory concentration (MIC) of the extracts was of 500 µg/mL, and no toxicity was observed against BGM cells. Vitamin C and total carbohydrates were not in accordance to the levels determined in the legislation. We used HPLC to confirm the presence of flavonoids. To the best of our knowledge, this is the first report of the antimicrobial potential of these fruit pulps. Our data open doors for more studies with chromatographic fractions and isolated flavonoids from these pulps.