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Use of different solvent systems for extraction of plant materials may cause variation in their bioactivities. The present study was conducted to evaluate the presence of different phytoconstituents and to compare in vitro bioactivities of petroleum ether, dichloromethane (DCM) and methanol extracts of Bombax ceiba (B. ceiba) roots available in Bangladesh. Preliminary phytochemical screening was conducted using specific standard procedure. Antioxidant activity of the extracts was evaluated using DPPH radical scavenging assay. Determination of total phenolic and flavonoid content was also carried out. Antibacterial and cytotoxic activities were investigated using disc diffusion method and brine shrimp lethality bioassay, respectively. All the experiments were carried out from February 2016 to September 2016. Phytochemical evaluation revealed the presence of alkaloids, terpenoids, carbohydrates, tannins, flavonoids, saponins and steroids. The methanol extract showed the highest DPPH radical scavenging activity and had the highest phenolic (187.42 ± 3.77 mg/g, GAE) and flavonoid content (74.67 ± 4 mg/g, QE) followed by the DCM and petroleum ether extracts. The extracts showed positive correlation between DPPH radical scavenging activity with the phenolic and flavonoid content. All the extracts showed mild to moderate in vitro antibacterial activity with zone of inhibition ranging from 7 mm to 13 mm. In brine shrimp lethality bioassay, the observed LC50 values for petroleum ether, DCM and methanol extracts were 70.72 μg/ml, 37.72 μg/ml and 22.58 μg/ml, respectively which revealed strong cytotoxic potential of the extracts compared to the positive control. The results indicated that B. ceiba roots could be a very potent source of natural radical scavenger and cytotoxic agent.