Colorectal cancer is the third most common malignancy that leads to significant mortality around the world. Chronic colonic inflammation could induce a protumor effect by the massive release of pro-inflammatory cytokines, facilitating migration, invasion, and metastasis of malignant cells in colorectal cancer. Therefore, developing a combination regimen of anti-inflammation and antitumor therapies is a promising strategy for the treatment of colorectal cancer. Here, we report that tannic acid-containing nanoparticles, formed by a turbulent-mixing technique, have exhibited uniform size, high stability, and pH-triggered drug release in the gastrointestinal tract, and could overcome intestinal mucosa for drug delivery in the colorectal region. As a drug carrier itself, with potent antioxidant and anti-inflammatory properties, tannic acid-containing nanoparticles showed great therapeutic effect in preventing the development of colitis-associated colorectal cancer (CAC) through oral administration. Furthermore, we used a therapeutic nanocarrier to deliver chemotherapeutic drugs for CAC treatment, generating lower systemic toxicity and superior antitumor performance through concurrent anti-inflammation and antitumor treatment. As a result, we confirmed that the drug carrier itself with therapeutic function could improve the overall therapeutic performance, and provided a safe and effective tannic acid-containing nanoplatform for the prevention and treatment of colon diseases.