As a common harmful pollutant, cadmium (Cd) can easily enter the human body through the food chain, posing a major threat to human health. Gut microbiota play a key role in Cd absorption. Docosahexaenoic acid (DHA) is thought to have a potential role in the treatment of Cd poisoning. This study investigated the therapeutic effect and mechanism of DHA in Cd-exposed mice from the perspective of the gut microbiota. The results showed that DHA significantly increased the Cd content in feces and decreased the Cd accumulation in the organs of mice. The gut microbiota results showed that DHA significantly restored the abundance of Parabacteroides in the gut microbiota of Cd-exposed mice.Parabacteroides distasonis(P. distasonis), a representative strain of theParabacteroides, also showed Cd- and toxicity-reduction capabilities.P. distasonissignificantly restored the gut damage caused by Cd exposure. At the same time,P. distasonisreduced the Cd content in the liver, spleen, lung, kidneys, gut, and blood to varying degrees and significantly increased the Cd content in feces. The succinic acid produced byP. distasonisplays an important role in promoting Cd excretion in Cd-exposed mice. Therefore, these results suggest thatP. distasonismay have a potential role in DHA-mediated Cd excretion in Cd-exposed mice.