Activated carbons were used to examine their performance for the separation of undesirable colored materials from culture broth containing hyaluronic acid. Six local samples and a NORIT ROX 08 were tested, whereas the latter was mainly studied under batch and continuous modes. The optimal wavelength for the detection of colored materials was 330nm. The optimal choice of NORIT ROX 08 provided 30% colored residuals with 96% hyaluronic acid recovery of original broth in batch experiments. The nonlinear adsorption behavior of protein and colored materials with activated carbon (C) was correlated by a Langmuir equation to give 18C/24+C and 500C/892+C for protein and colored materials, respectively. It appears that colored materials were composed of 78% protein and 22% glucose residuals on the basis of clearance results. A microscopic study using a scanning electron microscope suggests that regeneration of used activated carbon with 0.1N NaOH and hot water was not satisfactory. The present study proposes that the continuous monitoring of colored materials during purification can be accomplished by Installation of a UV monitor commonly used for continuous detection of protein during the process, as resulted from the significant correlation of color (A330)=0.353protein(mg/ml)+0.1(R=99.7%).